Just got off the phone with Jeff at Keith Craft - lots of great insight! Here's some points as I recall:
1. When adjusting hydraulic lifters, when you initially adjust the lifter it may move the valve off the seat and the engine will have to make several rotations for the lifter to prime and the push rod to center on the lifter cup. Then the hydraulics will go into effect and the valve will close.
2. Based on above, I can't actually test compression while lashing the valves as the valves won't be seated. Thus, should only do a leak down test when the engine is warm.
3. To lash the valve, back off the adjusting nut until there is play (lash) in the rocker arm. Now spin the push rod with your fingers while tightening until you can feel that there is no lash - then go another 1/4 turn. I was tightening until I couldn't spin the push rod with my fingers and then going an additional 1/4 turn - too tight per Jeff. However, these lifters are for a 460 engine and have enough play to potentially go 1 - 2 turns past zero lash
4. Aluminim heads when cold may not be completely symetrical and need to be warm or the valve guides could be "sticky."
5. On aluminum heads when cold, carbon will stick to the valve seat and potentially keep the valve from seating. When I tapped the valve, I probably knocked some of that carbon loose and allowed the valve to seat
Yesterday, Keith said he was looking in to writing a book that is full of these types of tips. He said he's found - and I agree based on books I've seen - that most books tell you the theory and basic how tos, but don't give you the real life tips on how to deal with issues and fixes for all the types of things that seem to be coming up in a lot of threads here. I told Jeff he needs to make sure he gets co-author credit
Now, back to the garage to put the tips into action!