BOZ at higher voltages+funky PS anyone?

hi all,

this is my first foray into a more *serious* piece of non opamp SS and i'm looking to do something interesting.

NP in a few older threads said the BOZ mosfets can be run at higher voltages and more heatsinking with perhaps an increase in linearity. sounds good and quite doable to me...i've got some tube power supply trannies in my arsenal box and can get all kinds of different. the BOZ needs 40mA per channel right? in theory, couldn't i get away with an actual tube voltage regulated ps? at what voltages, even with different IRF mosfets can i take the design to without watching it explode?

what would i need to change on Mrs. Zen as far as parts go? larger R102 and R104? how can i calculate that sort of thing?

any advice, direction or ridicule would be appreciated.