Couple of things for you-here's a great link to a complete how-to on covering with tissue:

http://www.aalmps.com/covering.htm

Just noticed your question about prop size-yes, you'll end up running a prop that is larger than scale. Just goes with the territory. An effect of shrinking the size of the plane without shrinking the size of the air molecules it flies through.

The build is looking pretty good. Just wondering how you're gonna get the horizontal stab un-glued from the plans.

And here's a photo of a lighter way to make tail surfaces. It is thin strips of balsa soaked in warm water and wrapped around a cardboard or foamboard pattern and glued with a bit of
Titebond. Way stronger and vastly lighter than the Guillow's way with the huge flat pieces.

Kelvin