Since this thread is back on the plate discussion, wanted to follow-up with my findings from the Rev A slider stuff-
So it does appear that, if you wanted to go this route in the future, you could actually offer a Type-S plate that worked with the stock HHKB sliders and likely wouldn’t require too much work on your part to change the mold.
The OG Topre slider/housing configuration for 1u keycaps was actually a stock slider (with the “tongue” on the base cut off of it) that used the standard ~0.5mm foam disc that they still use today, and then the housing itself was reconfigured to account for it-
You can see that what they did was take ~0.5mm from the barrel guide (marked ‘A’) from the stock, and then used the additional space to increase the “ceiling” (marked ‘B’) of the Type S slider by the same amount. This afforded the space for the 0.5mm foam disc to fit without reducing tactility and keeping the keycap resting height consistent across stock/silenced.
One thing to also note is they appeared to make the barrel guide more of a complete circle (instead of semi-circles) to help reduce (the likely now-worsened) keycap wobble, so that is something you could potentially apply to any slider housing in the future (note that this makes it more difficult to push sliders thru that still have the “nub” on the barrel). Pic example here (new user limitations are dumb): imgur / IusmQsO.jpg
So for you to offer your own Type-S plate, you’d basically just need to make the additional mold (and I’m sure your bank account just leapt out the window), and then partner up with someone like Deskeys to include their 0.5mm silencing rings in the sale of the Heavy Grail Type-S.
I did also look at the stabilizers, and it’s a little more iffy on ease-of-implementation in a Type-S plate. The 2.25u sliders actually have the same overall thickness and barrel length as a stock slider (and this was consistent with both the Rev A and Rev B Type-S Realforce sliders), it’s just they increase the height of the “ceiling” on the housing by ~1mm, drop a ~1mm thick ring on the slider, and then cut off a piece of each end of the actual stabilizer portion of the slider so that it fits better in the taller/angled ceiling.
So you could include the taller housings, but sourcing 1mm rings (and doubling 0.5mm rings results in terrible silencing if you do it the wrong direction, I tried all 4 configs and only 1 sounded properly silenced) and then still having to deal with the corners on the slider hitting the angled walls in the “ceiling” when the keycap is pressed at an angle might make that offering less appealing.
Saying all of this, obviously if you’ve already achieved the impossible feat of creating your own plate that’s capable of mass-production, and have custom keycaps in the works, then the technical challenge of creating your own Type-S sliders (comparable to the current Rev B purple sliders) to work with the standard Norbauer plate seems like it would be pretty trivial for you (and I imagine it would cost much less to mold/manufacture as well), so that may be a better approach to take if you would like to give us noise-conscious clackers an option down the road.