Dang,

How long have you been working on this?? Looks awesome!

Here's a tip for next time, or for someone who hasn't gotten to that part yet:

On the control-horn hard-points in the ailerons and flaps--rather than cutting the rectangular holes then removing the balsa and foam to glue the plate in, install them before you glue the balsa leading edge on. Take a small-diameter hot wire (I use the back end of those 12" 2-56 rods that I've got all over the place) and melt a slot in the foam. Don't do it in the middle, to it on the appropriate side against the inside of the sheeting. It doesn't really matter if the hole is oversized a bit because you're gonna fill it with epoxy. Once you've got your slot, test fit the plate. When it fits loosely, fill up the slot with 15 or 30 minute epoxy (5-minute if you're really quick on the draw or you've done it successfully on one), then slide the plate into the slot. Wipe off the epoxy that squeezes out and make sure it's as clean as possible (I use masking tape on the wood to keep the glue off). Let it cure, then face the leading edge with your sanding bar before you glue on the leading edge balsa per instructions. Take a Sharpie and mark where the plate is! Otherwise, you're gonna be in the bathroom with the lights off, shining a Maglite through it to see where the dark spots are (ask me how I know this...).

It's faster, easier and you don't have to try to sand hardwood down to be flush with balsa. It'll actually take you less time to do it than it took me to write this