RE: Goldberg Ultimate
mono wing:
CG 10-300 ARF uses 2 4-40 hex head bolts to attached upper wing.
I use lock nuts and with the right tool, it is easy and fast to attached at the field, not to mention, safe.
some plywood may be needed to reinforce that specific area but after 7 years of flight on my ship, I have seen no issues on such an attachment.
enjoy.