Sorry about that Dennis. I got lost somewhere in the thread and got off on Hucks, I see you said right off you had Bendix.....

Unfortunately I don't have a knowledgable answer to your question. I would guess that a proportioning valve wouldn't be necessary for Bendix drums on front & rear but thats just a swag on my part.

You could order a dual MS w/the proportionng valve and try it both ways, that is with the valve disonnected and then connected to see which way works best.
Good luck and sorry about the hijack.
Dave