Instead of building a full-height wall you can indeed build a half-wall or a pony wall. Or you could build a really, really, really short pony wall, otherwise known as a "curb".

Shower curtains are helped by a little bit of "vertical curb" at the shower floor, that will prevent the bottom edge of the curtain from flopping out onto the bathroom side of the curb.

You could easily carry your curb around two edges of the Kohler pan to make it look uniform.

You could also use the 48" shower pan and then add a bench to one side, as shown in this thread:

Here is a link that might be useful: bench next to shower pan

Thank you both! A "curb". That's a useful word! Thank you for supplying the vocabulary. And for the idea of carrying it around to the other open side as well.

crl - Here's a picture of my Kohler pan with a half wall installed on the left side. I guess you could just envision that as a really, really, short wall for your installation.

Two curbs would create a trip/safety hazard situation. If you do a pony wall, it needs to be at least waist height to provide visual cues as to where it is located and to provide a physical barrier as well. Otherwise, in an common situation where you close your eyes to rinse your shampoo, you can become disoriented easily and trip over the curb.

Wouldn't that happen with the one open side? Just trying to understand how two open sides would be different from one open side in that regard?

Thanks!

Because the open side will be behind you rather than to your side. Stepping back, and misjudging it, would be a real possibility and hazard.

Hmm. We had one of those j-shaped tubs in our first house which was this configuration, although bathtub height, of course. Definitely not waist high. Never had any issues and they are pretty common in older homes, though no longer widely available for purchase. Different because people expect it?