Combination Valve Install question

It will take care of itself when you bleed your system.
That said, be prepared for leakage, a common problem with the repro valves.
Search the brake forum for the subjects of "leaking proportioning valve" or "leaking combination valve", etc. and "annealing copper washers".
Also, open it up and clean it out as best you can, common to have manufacturing debris inside of them that makes them hang up when in use.
Best of luck!