I have finally adapted my model, for the Bambu, line of caps of bottles, that I use for priming the miniatures of 28/32mm for mass-priming. (Sorry for the delay, but the fastening area gave me printing problems with bambu models).
I use with combination of my Miniature painting holder.

I don't glue the miniature to the cap; instead, I use blu-tack type putty to hold it in place