Proportioning Valve - which one?

I'm converting to the disc brake setup from a BBP 75 Duster, from the 10 " drums the car had on it. I was going to grab an after market pro valve, but would like a little bit of guidance from the group here, as to which one I should get. It's the only piece I haven't picked up yet.

It's a manual brake car and will keep the drums in the back.

Thank you -