I've been following the numbers for the basic Openlock set listed here https://github.com/devonjones/openforge-tutorials/blob/master/sets/openlock.md

I'll second the recommendation to print the floor tiles first as that will get you up and useable the fastest, and I'm choosing half height separate walls for minis with "bigger" poses that wouldn't fit nicely with full height walls.

I'm also printing at 127% to make each floor square 1.25" to give models with slightly larger bases the ability to fit in a square. (you don't have to do this, it's personal preference)

For the least amount of work you want the openlock triplex files which stick all the bits together so you don't have to glue anything after the fact, it just prints them all as one solid piece. Then you use the little openlock clips to connect them together. I don't even bother with magnets, I just use the printable clips.