I've installed my side cases. Thanks to everyone for their advice.
I wanted the side cases to by easy-on and off. It just takes a few seconds to remove each case.
I mounted pieces of aluminum u-channel to the backs of the side cases, which rest on the bottom tubes of the Givi racks. I lined the u-channel with weather stripping to prevent rattle and abrasion and also to create a snug fit.
For the top mounts, I used the Monokey attachments that came with the Givi racks. I just flipped them to the other side of the racks, which gave me threaded attachments points. I have a couple of bolts inside the top of each case.
So, with just a screw driver, I can remove the two top of bolts inside the case, then lift the case off of the rack.
I have around $250 in the racks and cases: The Givi racks were $171. The 2 Apaches cases were $30 each. I ordered the u-channel online for less than $2 each pre-cut. The packet of weather stripping was less than $5. Bolts, washers, etc. were around $10.