Ok, I will add my 2 cents here Rav because you're a good guy. I don't agree with some of the stuff here, and I do agree with other things.
First of all:
Are you flight metaling this F100 or all paint?
If you are using flight metal, remember that flight metal is aluminum tape, being aluminum you SHOULD use a self etching primer on the area's you intend to paint or adhesion will suffer.
As for the grey gelcoat that BVM uses, I agree, don't sand through it, the pinholes under it are awful. However, my recommendation is this:
1. Wash the crap out of the gelcoat before you start doing anything. DO NOT use isopropal alcohol. IF it does find it's way into a pinhole, you will have issues. It is not an appropriate pre paint cleaner. Before you start, wash all the parts with a hot water solution and tide laundry detergent. The POWDER, not liquid. This cuts grease and waxes very very well and does not leave a residue. Once it is washed in that, wash it again. Then use a wax and grease remover like PPG DX330 to clean all the parts. Do not just leave the 330 on there to evaporate, use a clean microfiber to dry it all off.
2. Next, I would recommend sanding all of the gelcoat with 320 to 400, this is another one where I recommend dry sanding this. IF you do wet sand it, leave it for at LEAST 24 hours to dry so that any water that made it into seams, pinholes etc can evaporate out. Dry sanding is easy to deal with, use an air blower when you're done to blow the crap out of everything. Wet sanding will dry dust into holes or seams which can fool you into thinking they are filled. Blowing air on them won't always clear the residue but when you get solvent on there, it can lead to fisheyes, bubbling, or just plain poor adhesion.
3. Once everything is sanded, do any filling you need to do and feather out your fillers. You absolutely can NOT wet sand filler. It is absorbent like a sponge and I have seen bodywork that was wet sanded lead to moisture problems under the paint months after the fact.
4. Then prime the jet. Forget the fact that there is a gelcoat, prime the whole jet. This will give you an even surface for paint, it seals your body fillers, and will either fill, or show you any pinholes. If you do find pinholes, use a paint brush and push some primer into those pinholes.
5. Now you can wet sand, use 800 grit paper wet and sand everything until it's even. Use a guide coat, all a guide coat is is a contrasting paint that you mist over the primer, when all of the misted paint is gone, you've sanded all the primer. If you have low spots or scratches, the guide coat lays in them and you will see them much easier.
6. Next, whatever the overall color of your jet is, spray it all. Yes, it will add a little more weight, but unless you are hammering the paint on like a car with a big gun, it will be minimal. Do NOT over reduce the paint, I don't care what multiple guys on this forum have said regarding over reducing, these paints are developed to mix a certain ratio. Over reducing will dimish your coverage, film build, and adhesion. To get the same coverage you'll end up needing extra coats anyway so why bother doing something that the paint is not meant to do.
7. Tape, 3M fineline tape used to be the best, but the new darker blue stuff sucks. There is an orange fine line tape from a company called FPS (I think) that is thinner, and works much better than the new 3M stuff. Use the 1/8" if you need to do curves, 1/4" for straight lines. the wider tape is easier to keep straight. I REALLY discourage you from using sign vinyl to mask with. There are many reasons. First, it is to high of an adhesion and your chances of lifting the underlying paint is much higher. Second, IF you put it on a little to early, the solvents in the paint will cause the adhesive to come off of the tape and stick to the paint, then you're screwed. The other issue with the sign vinyl, is the solvents even being sprayed over top can attack the vinyl enough to cause the adhesive to come off and stick to your paint. The other issue with it if you are going to cut your curves once on the airplane is the actual cutting, if you cut any deeper than ONLY the vinyl, you have comprimised your underlying paint coat, and potentially even the fiberglass under that. There is actual paint masking vinyl that you can buy, but it's meant to be precut on a vinyl cutter and then applied as a paint mask.
8. When you lay on your next colors, do not leave the tape on for long, you want to peel the tape off about 5 to 10 minutes after your last coat. Any longer and the surface of the paint skins over enough that it can leave a ragged edge. Wait until that paint coat is totally dry before masking over it though. PPG DBC Basecoats (or most any solvent based base coat paints) are dry enough to mask over in 30 to 45 minutes.
9. Once you have all your colors on, get the clear on. You realistically only have about 36 hours before clear SHOULD go on and even that is pushing the time a little. If for some reason you have to leave it for a couple days, spray on a coat of PPG's DBC500 so that when you come back to it you can scuff it with a grey scotchbrite pad before continuing so that you still have good adhesion. This one I cannot stress enough, and while many do not share my opinion, my paint jobs on jets are very light and extremely rich. DO NOT reduce your clear unless the manufacture recommends it!!! You will lower it's adhesion capabilities, it will not flow as nicely, you will increase your chance of runs, Decrease the quality of the gloss, it will shrink more, it is simply not something worth doing. 2 coats of clear is more than enough for a beautiful finish without adding much in weight. If you are doing a flat clear, my recommendation is to spray two coats of gloss clear, let it cure, wet sand it all with 800 grit, and then spray ONE even coat of flat. This will eliminate all the goobers you might have gotten while color painting and clearing, you can apply markings over the sanded gloss clear, and then spray the flat over all of it.
As for setting up a paint booth, you really want to create a negative pressure in the booth, this means you want to have a filtered intake air source with a fan that is pulling the air out of the booth through filters. You can wet the inside of the booth, but if you are using all plastic in there I would advise against it, you will be creating to much humidity in there unless you are moving enough air. If you are going to wet it, do so about an hour before you are going to paint to knock down the dust and run the fan to pull the humidity out.
Anyway, take it for what it's worth, but with well over 1000 motorcycles to my name, many many cars, and at least a couple dozen jets, I know that my methods work and produce excellent results.