Booster to proportioning valve (combo valve) line size

[ChadW]

I am setting up my disc/drum master/booster/combo valve and am getting ready to make the lines that go to from my master to my proportioning valve...My valve is located in my frame rail so my lines from the booster to this valve are a little longer than most...the master has 2 different size ports, forward most port 1/2 and port closest to firewall is 9/16. The combo valve has 2 different size ports for the lines coming from the master as well...1/2 in front and 7/16 in rear on valve....Cpl questions i hope someone can straighten me out on....#1...line size, do i need 3/16 or 1/4 line going between master and combo valve? #2 does it hook up front to front , rear to rear or ?