I have tried the resin-cast options and they are very nice to type on. They keep the shape of the hi-pros exactly since they’re molded from the original caps. I believe that I’ve tried both Blizzard and Idea23 and they were pretty much indistinguishable to me.
If you’re putting hi-pro on an hhkb you’re going to sacrifice something in the way of legends or profile so, as long as you can touch-type, resin-blanks might be one of the “purest” options.
I did have one where the stem broke in half. it still clipped in because of the way that topre mounts but it left the rest of the stem in the housing. Idea23 at least promises that they will replace defective caps.