I haven't been casting for very long but I've been reloading for decades. In my limited casting experience, I've tried a few molds but the RCBS 38-150 SWC is without a doubt the one that I will rely on. It was recommended by members of this forum ( with a Lyman 358477 as a close second). That has proven to be sound advice and it is now my go - to 38/357 bullet.
With 20:1 or COWW alloy it drops out of the mold at around 160 Grs +/- and a little over .359" . The profile is basically a Keith SWC. I can't imagine a need for a gas check in a 38 Special bullet and I prefer simplicity over complexity any day of the week. I think sometimes people have a tendency to wander around looking for the next best thing when they already had something that is, "as good as it gets".
P&P