Nice to see another Goldberg thread booya!!

I wouldn't enlarge the ailerons they won't make the plane perform any better than stock. I fyou take your time with them and make sure you bevel the edges accurately to give maximum throw you will get alot out of them. Even on 50% throw mine will snap roll on a dime into a ball of smoke and full aileron either way will induce a spin like a blurr. I just don't see the need to mess with the stock set up personally.

I second Dave - no need to reinforce tail. Will just add more weight that you DON'T need or want. With the sheeting and proper use of epoxy to glue tail feathers on you won't need it.

Tail mount servos are good for elevators. Go with hitorque mini servos though - my standard ones are overkill when you have 1 per elevator half.

I toyed with the higley top wing mounting mods - didn't bother apart from the guide tabs for the bracket that the top wing slides onto (a MUST DO). Properly done as higley suggests (like mine!) its robust. I don't use a rubber band I use electrical cable ties. Solid and will not break like a rubber band. They are so cheap you just cut it off when you need to remove the wing.

I would glue some aircraft grade 3/32 (3mm roughly) at least ply under the whole horizontal former that the cabanes bolt onto. Far stronger as this area is subject to a little torsional twist and stress. Worked a charm on mine. I would make a solid doubler (fuse side to side) next time round though.

If in doubt read my thread haha It is a good synthesis of a lot of mods other people have done and there is good building discussion and guidance there from all here at rcuniverse.

Enjoy the build, I found mine became a real journey and I was amazed to watch it take shape and turn into the beast I now have. It will reward you everytime you fly.