Wade is correct, I use a bump switch to turn the engine to the desired timing location as I adjust.
I use a finger spin on the rod to tell me the rocker is at zero lash.
I do not add anything to the setting. I just leave it at the top and lock it down.
Note: if you do not prelube your engine before you do this, you can be adjusting all day. Get a good pressure reading before you set your hydraulics. This keeps the cups from giving as you adjust.
Just my $0.02