Plumbing a combination/proportioning valve

I have a universal "GM style" disk-drum combination valve (includes a proportioning valve), like the one MP Brakes sells and I'm not sure about plumbing it. I know what goes where, but I'm not sure about the SIZE of the lines. One site (that I can't find now) said that all lines had to be 1/4", which seems too big. My brake cylinders and hoses are all 3/16". Can I use adapters and use 3/16 like everywhere else? Or do I need to use large lines to the valve, and adapters stepping it down to 3/16 after the valve?

Yes, I have a 10# residual valve for the rear and a 2# residual valve for the front disks, in case you were going to ask. This is for my Econoline, if that matters.

 

There is no reason to use one size line over another. Use what fits in the holes.

 

flat-bill wouldnt larger lines reduce pressure? I know a roundy round catalog
I have sells larger lines for this purpose.

 

I used all 3/16 , works like a hose
Ron