That's the first time I'd heard of PnPfocus. Looks cool - just for future reference, do you know much about specific motor models that have good torque etc and are as good as the commercial motor focusers? Also any good sources for mounting hardware etc?
There are a few described in the PnPFocus github page - I am using the 17HS13-0404S-PG27 NEMA 17 motor and it has plenty of torque. Most focusers don't need much torque so this one may be overkill - and it is heavier than other options.
With respect to mounting hardware, there are some that do 3D printing, but for my Moonlite focuser Ron added in one of his brackets and I spent an hour or so at the drill press making an adapter out of some scrap aluminum to get everything dialed in. I made one out of a thin piece of plywood first and it worked fine - I even contemplated making one out of plexiglass from an old clipboard, but the aluminum piece, once painted black, matches the Moonlite gear and looks cleaner.
At the end of the day, there are not too many forces that you have to overcome, so you can use whatever material you are most comfortable working with.