"Here's a few more questions.....
Why rub down the surface to a super smooth finish, then apply a stainer. The fact that the stainer is a liquid means that the surface pores of the mahogany will swell so it will have to be sanded again. Why not stain the mahogany then sand smooth?"
Wood working in general, the smoother the wood is, the better the final finish will be, especially if you're looking for a glass
smooth finish. Sand it smooth, then stain it. Wait for the stain to dry, this is more important for oil and water based stains. Oil stain takes time for the oil carrier to evaporate. The same holds true for water based stain. Solvent based stains dry quicker, but can sometimes affect the glued joints. After the wood dries wait another day and sand the wood smooth again.
"Why does the surface have to be super smooth. Won't the resin adhere better to a ''not so smooth'' surface?"
Again here, the smoother the wood is the better the final finish.
"Won't the surface look great under several coats of resin and laquer even if it is not perfectly smooth?"
Try sanding a scrap piece, stain it, sand the left hand side only, then coat it with resin, sand the left hand side only, apply your finish lacquer coats. Do you see enough of a difference to bother you? That will give you your answer.
"Does anyone know what colour stain is best for the deck and what colour is best for the king plank and side decking plank?
I realy like the 2 tone decking it sets off the model nicely."
Only you can be the judge of what colors are best. Try looking at classic wooden boat pictures and find a color scheme you like. Then you can attempt to reproduce it on a scrap piece before you commit to doing your boat. Fater you stain the scraps you need to resin coat them to see the final color. The resin will darken the colors some.
"The model is fitted with a Dumas 3 blade prop and a Dumas motor, (9 - 12 volt / 2 amp max, stock nmbr 2005) does anyone know how it will perform with this motor, or should I fit a different motor?"
I would suggest you try it the way it is. You may like it enough to keep it like that. After you run it a while like that, you can all ways change it later.
"Sorry for the questions folks...I usually build model sailing boats so this is a first for me."
Don't be bashful, ask away.
I will second what Rich said about the book "Mahogany in Scale".