Dwango,
Just an FYI. On my very first ARF an LT-40 I couldn't figure out how to keep the two wing halves flush while the epoxy was drying. So I clamped the wing at the aileron cutout and taped the rest. I then stood the wing vertically!! I checked on it for a half hour and went to eat. Long story - when I came back the next day the wing had a 1/4" twist. My fellow club members thought it was hilarious. Later they told me to prop one end of the wing end up flat on the table. Ah well. So I cut the wing in half. Glued each half together with one end propped up on the table. Voila a straight wing. All the hobby shop had was 1" wide fiberglass tape so I pealed back the covering and epoxied it completely around the wing.

That was 4 years ago. The wing has hit a pine tree hard enough to crush the leading edge back 2". Repaired it then flew it into the tops of some poplar trees learning depth perception. It has survived full power dives, full power snaps, cartwheels that required replacing a wing tip. But the center joint has had no problems - ZERO - no dihedral brace and only 1" wide fiberglass tape with epoxy holding the wing together!

I fiberglass all my wings now. I usually use 3-4" wide tape but was amazed at what 1" tape can do if properly applied.
John