I have been working on the wing getting ready to install the Aluminium joiner 6 x 50 mm
I have epoxy the alunminium joiners in the front of the wing
They also use a nice plastic system for the aluminium joiner to go into
and the rear part of the wing gets 4 x 40 mm bolts threw a plywoood plate for the hold down on the wing

Well I just found a problem with mounting the wing
if you use their system the wing will not sit correctly in the wing saddle just by the the thickes of the plastic
support they are using
it is only a 3 to 4 mm
I think they have their drawing showing it going in the wrong way