Putting around 5 levels worth of APs into HP for the next 5 levels w/o HP-washing?

IMO, if you're going to do that, it's wiser (again IMO) to scroll gears for HP. It's a bit easier when you decided to say "dammit" without NX. I am facing the same problem as you, so I decided to scroll my zhelm with HP instead (I can pretty much get a zhelm any time thanks to my uber zleader) as well as other stuffs.