For the small PFA carriers you might check with one of the Silicon wafer
polishing houses that do 1" wafers to see if they might have one or two
to sell you.  Wafer World, Polishing Corporation of America and Silicon
Specialties all do 1" Silicon wafers and likely have PFA for the
etching.  There is another 'boat' other than the one you showed. It is a
W boat with a lid that will hold multiple diameters from less than 15cm
to more then 25cm.

Cheers
Ken Smith