[Phillyfanfrombirth]

I'd run the engine, pull the valve covers off, grab a pushrod on a valve that is seated between your index or middle finger and your thumb, and have a socket on the nut...

If you can't spin the pushrod with your fingers while the valve is seated, back off the nut...

If you can spin the pushrod relatively easy with your fingers, then slowly tighten as you keep spinning the pushrod. When you can no longer spin the pushrod, back off nut until you can.

Go through the engine progression until you have them all adjusted. If there were any pushrods that wouldn't turn, loosen them until they do spin and note their position... put the valve cover back on, and start the engine long enough to get oil pressure back. Go back and check that all pushrods are on the same brink of being able to turn them.

This may take 2 or 3 tries to get them all at the same level. If they are already tightened too far, the lifters will have the hydraulic pressure removed from them, giving you the false impression that they need tightened. When you start the engine back up, the hydraulic lifters will solidify and give you an accurate gauge of where you are.

You may even wish to back off all of the rocker arm nuts until they are noticeably loose (not so loose that they will fall off, but loose enough that there is some play)... replace the valve cover and start it just to start from scratch and so that you know that nothing is already too tight.