Hirsbrunner valve and felt question

[sousakrue]

I have a Hirsbrunner HB-12 F tuba made in 2009 and would appreciate some help with the following questions.

Question 1: Does Hirsbrunner put the same piston valve block on the HB-10 and the HB-12? I'd like to get a PVAK made for this instrument or stiff washer set to replace the current felts.

Question 2: I would also like to replace the felts on the top of the cap (there are no felts under the button, only on top of the cap) where might I find these large colored ring felts? These are quite worn as well. My other Hirsbrunner felts were different on the top cap so I'm a little lost with the alignment felts being in the top cap not under the button.

Thanks for your help.