Q. What were my tolerances for pieces that snap together?
A. In my case it's trial and error. The resource tiles are 0.1mm smaller than the resource base they fit in to. The number base is 0.0mm "smaller/same" than the hole it fits in to. Why the difference? I don't know. The size, shape and flow rate can all affect the final size. What I did was start with the same size peg for the same size hole and trial and error'd from there.
For this reason I'm tidying up my SCAD files so it's trivial for even OpenSCAD novices to change the tolerances and generate all of the pieces required. That's why it isn't up on Thingiverse yet.
I enjoy the undiscovered territory game. It adds a randomness to it which lets differently skilled players compete. I like the challenge of starting with poor resources.
I haven't weighed it yet, but I'm guessing I used something like 500g of ABS for the whole 6 players board. As you can see I used different colour ABS (black, white, blue, green, yellow and red) but I designed it so you can recognize the resources without the colours. So the whole thing could be printed in two tone, black and white, red and yellow... whatever.