SoaringAce
Hi:
I'm sure there are many viewers in RCU land that are real experts that may respond to your post.
I'm not one of those yet however. There are a number on RCU threads that exist on this subject for you to research. Go for it.

I just finished a scale build project--Stafford 1/6 scale Piper Comanche. I too was very concerned with weight, but really wanted a smooth surface ready to accept paint. I had previously experimented with polyester type resins but read that they tended to be on the heavy side. I went looking for a light weight solution that would give me a smooth finish that I could paint, A finish that would accept panel lines, rivets, etc.
I settled on a thinned one coat epoxy resin and 3/4 oz glass; then 2-3 coats of water based poly urethane; automotive lacquer primer/filler as the surface ready for painting.
Here is what I found to work out wonderfully, I am extremely pleased with the end result.
I choose Aerospace Composite Products EZLAM resinsystem, and their 3/4 oz glass. This is an epoxy that can be 50% thinned with 91% isoprople alcohol
One coat brushed on and that was that. Then 2-3 coats of the MinWax poly urethane; spray on primer, sand off, and you have a super smooth finish ready to apply panel lines, etc. The weight issue: I think I added less then 8 oz to the basic dry weight plane with the glassing and finishing up to ready to paint. . It will be around 11 # painted.
I have heard also that many people like the West system, which is also an epoxy based glassing system.
As to ease of doing this glassing project, it was a breeze to do. Very little sanding, easy clean up, very little odder
Hope some of this helps.

BobM
nauticom