At the spring pressure posted...you won't have any problems without banana grooves or rocker bushings.

They will work fine steel on steel, as long as you do not use any thick, paste-consistancy lubes on the rocker and shaft assy during assembly and do not overtorque (crush) the rocker shafts. Use a liquid type assembly lube only and mind the torque on the hold downs....more is not better....more torque causes galling because it deforms the shaft.

(I have used those rockers at 500lbs open pressure for several years for whatever that's worth, but I have not really put tons of miles on them either)