Not all Golf Tees are .20 some are .24 and I have had some bags that are .29
Measure before cutting.
Also some "16mm’ dice are WAY over, so measure and adjust the storage squares.
I bought different color dice and tees on EBay and Amazon in bulk.
The Eight Inch Version is at this link:
I have used shellac and sometimes polyurethane as a finish, and both work well.
I have put little stick on feet on the bottom, and have found that each corner of the puzzle seems to need one, especially if people lean on the puzzle as they play!