I have the same brake setup as you. I was told by Wilwood that a combination valve is not needed. They told me to use residual pressure valves on the front and rear. Also they told me to use a proportioning valve on the rear to set brake bias. Thats it.

From Wilwood Tech Center
Residual Pressure Valves
Use 2lb. RPV's when the master cylinder is mounted below the level of the disc brake calipers to prevent brake fluid from draining back down into the master cylinder. Use 10 lb. RPV's with all drum brake applications to offset return spring tension.

proportioning valve
It is typically installed in the rear brake line to reduce braking efficiency and compensate for premature wheel lockup; a result of incorrect front to rear brake bias. An adjustable proportioning valve permits incremental adjustments to fine tune brake bias.