I have been building for years and always started with 80 grit and moved my way to 320 grit.
I purchased a Razor Plane from the LHS made by Master Airscrew. It works great and makes
those major shaping jobs a lot easier. Wish I would have had this 12 yrs ago when I started
this hobby. Would have saved me a lot of sanding.

I recommend one of those and the Great Planes Sanders are excellent. When you buy the
5.5" ones they come with an assortment of sanding paper. I bought 3 when they came out
and keep each one loaded with a different grit. Saves time changing the paper when you
need it.

I am about finished with a 4*60, it looks like a totally different wing structure than the 40,
more spars, I figured it would be just a scaled down version of a 60 size.

If you need any help or get stuck there is a TON of guys on here to help. Just ask, and
remember there is not a stupid question.