Personally I don't silkspan profile fuselages.  It's a profile the finish isn't supposed to be perfect, and the silkspan is weight.  The bit of benefit to strength is marginal and as far as making the plane crash resistant, the goal should be to build the plane so light that nothing survives the potential crash.  Beyond that it's more economical and faster to skip the silkspan.  About the only benefit I see is reducing flex in the fuselage, but on a plane that size it shouldn't be a problem.  

If you do decide to silkspan the fuselage, cover everything, including the tail surfaces so that the entire surface is even.  I usually do my fillets first and it's been OK for me, but I think in the future I might reverse the process.  Either way shouldn't create any real problems.

I'm tempted to say that a silkspaned profile will actually take less paint to make a decent finish. It takes a TON of paint to fill raw woodgrain. Silkspan does stiffen up the wood quite a bit. It's worth the effort. Glad to see you're going to take the time to do it right. Profile or not, unless it's a throwaway model, make it look as sharp as possible.