I also have two Ferris sweeps. My error was that I bought 3 pin switched, which wont sit right in place without a case. 5 pin switches(those with the 2 extra plastic pins at the bottom), will sit perfectly fine and straight without a case. So if you have 3 pin switches, that could be the problem with the “bad looking grid”. I currently have a silent one with Gazzew Bobas and a loud one with Kaihl Owls.
Yes, propably. Or i think something like this would work fine as well: https://www.thingiverse.com/thing:5192069
(sry for the late reply)