Thanks for the input!

I was thinking looks not function, fuel tank in the nose.

With the tip tanks I am most concerned about negative aerodynamic consequences. I just like the way they look but they are not worth it if the plane becomes very difficult to fly. I can stand a reduction in roll rate. My plan is to carve them from a block of light balsa, slice it longitudinally and hollow it out then glue them back together.

I have read a lot in these forums about tip shape and how it affects flight characteristics. I am learning as I go. Is there a book that anyone would recommend regarding aerodynamics and/or design?

Yes, I was thinking the ailerons would be something like 1 inch at the root and 2.5 inches at the tip. I think I'll pass on this though, I had an intuition that they may produce negative effects although I didn't know what.

Boy-o-boy, I like this stuff!