Roller Rockers are now legal but I do not use them.
I can play with the pads on the cast adjustable rockers to
play with the rate of lift to get a bit of more lift earlier.
No roller lifters = they would be cheaper than the billet cams
and tool steel coated solids that are legal and most guys uses.
I use a hydraulic lifter with a ceramic puck (think space shuttle)
on the bottom and travel shimmed down to about .010 to cushion the
hard but fragile material!