My wife is an avid bowler. She has 6 thumb slugs for her bowling balls that she carries around in a pencil bag. When she takes one out, the rest fall over. This keeps them all upright and she can remove one, drop it back in, etc.

V3 is the smallest and most lightweight, and the holes are a little bigger so the slugs can just drop in and pull out with ease. V2 is bigger overall, but with slightly smaller holes so the slugs have a more snug fit and don't fall out as easily. My wife prefers V3. Neither version requires any supports.

No

I've printed this in PLA and also in PETG and both work fine. For printers having trouble with dimensional accuracy, especially on the X or Y axis, you may want to use V3 since the dimensions will be a little more forgiving.