Well, that's more or less decided me on the Crower #01475 you suggested. With the 112 lobe center and .554"/.545" lift (factoring in the lash) there will be no danger of valve-piston contact, as it's near the same as the hydraulic roller I've got in there now.
With the lighter solid-roller lifters it should be capable of buzzing to 6000 occasionally?
With the current cam it made 483hp at 5500 (limited by valve float) and 500ft lb at 4600. I guess the solid roller will maybe just top the magic 500hp....