what length should i cut it to?
Measure the length of each wing panel's tube and add that to the width of the fuselage as measured at the fuse's wingtube. The total of mine is 44".
how do i cut it? someone told me a dremel is a no no.
You might consider taking it to a machine shop. For something simple like cutting a wingtube on a bandsaw, they would probably charge a very small amount.
if i cut it as stock length, what methods/tricks do you use to keep the tube centered?
I was able to get a hose clamp between the tube in the fuselage and the former behind it. Put in the tube and tighten down the clamp.
Dan