721 canopy decks

[182ppl]

Please help. What is the proper order to rivet the 721 canopy decks for a slider canopy? If I drill the tops first the rivets along the longeron are near impossible, especially the 3 foward most rivets where the 721, main longeron and the foward most top skin are riveted together. Would it be a huge deal if I removed a small amount of the flange on the 721 near these rivets to gain a better bucking bar access?