I am building my second Flip and am able to do a few things I would have done differently than on the first.

Don't use CA Hinges. They will not last long on the Rudder anyway. The deflection required for 3D will break them prematurely. Sort of like bending a credit card back and forth a few times. An extreme example but accurate. Most CA hinges are a plastic center covered with an absorbing paper on both sides. They are strong and free at first but will fail. I have used the metal ones with mixed feelings about the epoxy bond of metal to epoxy to wood joint. Drilling these to pin them is a bummer. I have also used the !QUOT!Point!QUOT! hinges with success but don't think there is enough balsa deep enough to really hold them well. I am now using the Sig XX giant scale nylon hinges on my Flip with great results. Way better epoxy bond. The hinge pivot pin section is beefy and allows for tremendous throw. They are easily drilled for either a toothpick pin or what I do is a nylon 4-40 screw. I thread the whole drilling and hardened with thin CA. Once the nylon screw is tightened in place from the bottom, I cover the head with the clear Ultracoat strip I use to seal the hinge gap. The worst part about these type of hinges (metal included) is that you have to use alcohol to clean up the pivot right away. They will still be medium stiff initially but will work in. Sealing the gaps is mandatory on my planes.

If you have already used the CA hinges, don't worry. When one fails they can be removed if you carefully cut them at the gap to remove the control surface and carefully slip a sharp #11 blade down both sides of them and cut them free a little depth at a time. The Sig XX hinges require a slightly enlarged slot width and length anyway. Cost for 15 Sig XX hinges is under $5.00 but could be worth your whole plane.

I want to post this hopefully before you use the CA hinges. I have some other tips but the biggest second tip I can immediately give you is to take your time and be patient. The plane is kind of fragile so don't manhandle it while building it. Save that for the air. You are already ahead of me by knowing about this forum before you build your first Flip,

Good Luck,

Errol