OK, the only thing that I grossly disagree on here, is setting the lash.... if you have to do this..... If you do, you are going to "zero" lash, and then some fraction of a turn on the adjusting nut. The engine really doesn't care if the lifter is pumped up or not. In time, it will reduce pressure to where it needs to be....equilibrium, if it is "over pumped" which it won't be if you prime the system after you set the lash... If I was installing new heads on an old short block, there is no way that I could (easily) "unfill" the lifters to make this scenario suggested possible!
The important thing here, is that once you do set your lash up, with new lifters, rebuild, etc, that you prime the system to displace air. Your lifters may not be totally pumped up yet, but they will do so very quickly upon start....as they now have at least some oil in them, vs nothing. Pumping the system up by hand with a speed handle is probably the oldest method of doing this. Usually a few turns the wrong direction will result in "bloop...bloop...bloop"noises in the pan....reversing the direction will soon result in resistance to spinning....and if you have your valve covers off, you will be able to see the oil come out of the rocker arm tops! This means that your lifters are at least partially full, the pushrods are full, and everything in the engine is gonna rock and roll that first couple of revolutions when it starts! Doing this will let you get on with other important things.....like fuel leaks, oil leaks....etc!
If you really are concerned about pumping up the lifters as much as you can before start, you can crank your engine by hand, to the three degree settings that you used when you set the valve lash......prime the system a few turns at each position and you should be golden......now to figure where to put the distributor rotor....hmm.....
Cheers!

Steve