I have built two of the Flatana's.

I am not really suggesting anything here. Just what I have done that works.

I found removing the flashing with an exacto not quite enough or to much trouble anyhow. I simply drilled out the holes, easier but still tight connecton to the z-bend things. No slop....my bit is small but I forget what size exactly.
I also use light oil on those connections before making them.
I only use the stock plastic z-bands on one end. I use the tiny dubro ez connectors on the servo horns
For me its a must to insert the rod into the z before istalling. Its tight but once set its set.

I take the control rod and insert and glue to the z-bend thing on one end. I install and check the linkage for desired results. I leave the control horns off the control surfaces until last. Slide the assembly into the dubro connector mounted on the servo....0088oz each. Then clip the GP horn on the rod system and glue in place in the slot in the foam control surface. Adjustment is now possible so I tx center the servo at 0 sub and align the control surface then tighten the set screw.

Mine is a hoot to fly. flutter yes warp yes...its foam. Still for what it cost its impessive and I get to fly nearly every day with it.

Blue