What? No retracts?

For inserting paper tubes in a already-glued-up-wing: take a thin walled pipe big enough for the servo connectors to fit inside, sharpen the INSIDE with a round file or sandpaper, put a few nicks in to act as saw teeth, twist it slowly by hand while pushing gently into the wing ribs.

I wouldn't bother with it - too big a risk of cracking the ribs. With the flat-bottomed aerofoil you're not going to be performing whip-crack manouevers that might batter the inner wing with the leads, anyway. IMHO you're putting a lot of work in and learning building techniques, but your test horse is still a plow horse and not a thoroughbred. Unless you remove the dihedral and taper the wings you won't get the slow-speed stall response a warbird has. You still have the pendulum stability of the high wing. You haven't done anything to make the LT-40 squirely, but you'll need to work in some down elevator when you drop all that flap area and the wing ballons. You might not be able to get it to come down at all!

In the old days (oh, here we go . . . ) we bashed Ugly Stiks to experiment with such things. At least you'll have a stable platforn to experiment with control changes (and getting used to manipulating them without looking away from the plane) - you just won't see much effect. Kit bashing is almost as much fun as flying. A tail dragger, eh? Did you move the wheels up so that the axles are about 1/2" ahead of the wing's leading edge? Doesn't look like it from the picture. You'll have to. Enjoy and keep the pictures coming.

Our club president is making a twin-engined float plane from a LT-40 in a construction class we are holding with a local Explorer post. The other four planes are stock LT-40's. (3 'adults' from our club and 16 kids. I'm learning a LOT about correcting mistakes.).