I touch-type on a blank HHKB, and I don't want to look at the keyboard when I type.
There's a problem when I want to type faster the four keys next to '0': '-', '=', '\' and '`'. I make more typos and I am not sure if I am on or certain key or not if I don't look at it.
I will help to have some key caps that are textured differently for these keys.
For example these:
(These are called "Bro SLS" AFAIK)
I like the "Bro SLS", but I know how they're priced in the marketplace. I'm not ready to spend the money of a whole set of GMK key caps / a whole Korean keyboard kit / 10+ used IBM or Alps keyboards on one or a few keys though.
Please make me an offer or a suggestion.