There is far more to it. You have spring rates and installed height to get a certain open and closed load. Sometimes shims are needed, extra clearance of the guides are needed or cutting the pockets deeper. If you have a reliable engine or cylinder head shop they can set this up for you. Do this wrong and you can have bent push rods, flattened cam lobes, valve float, destroyed seals, and possible rocker to retainer interference.
I would also have the heads gone over. A shops idea of rebuilt can vary, greatly.