I would just slather the epoxy on the ribs and wing joiner and put it together.

Notes:
Most wing joiners are angled for a slight dihedral make sur you DON"T fotget the wing joiner and you put the wing joiner in PROPERLY!!!

Have some isoprpyl alchohol ready for epoxy clean up as epoxy will ooze from the joined sections.

Clamp it the best you can and allow it to fully cure.

MR G