Leveling the mpcnc

how do you guys go about leveling the MPCNC? I am 3d printing shims out of PLA and using putting them in the sockets of where the conduit sits.

I use a block of wood. Cut it the height you want under the lower rails. Then start at one corner and stick it under the rail. Tighten down the screws, and move to the next corner.

ok then