One of the problems with using a foam master is that you can't "climb" on a piece of foam to test the shape. It's nearly impossible to tell if a given shape is going to be comfortable until you hang your weight from it.

The first time you can climb on a foam "master shape" is with the production version. Even if the shape sucks, there is little incentive for a plastic hold company not to add it to their hold line because they've already made the mold.

I've even seen pictures of actual foam masters alongside actual holds in one plastic hold companies catalog. Obviously, they didn't have the final molds finished in time for the catalog so they used the carved pieces of foam for the catalog photo.

How arrogant to think that some carved shape is going to climb well just because it "looks" pretty.

We use an intermediate step and make a "synrock" master before we make our final production mold. We climb on the hold before we decide to make the mold or chuck it. About 20% of our holds we decide "not" to make. Our rheological-forging process yields far more comfortable shapes than is possible with carved foam and yet we still reject a percentage of our shapes after climbing on them.