It's a matter of common sense, which is almost illegal these days. The whole point of a raised-RPM initial engine run is to prevent scuffing the camshaft lobes while the cam and lifters establish a running fit with each other. Roller cam engines don't need the cam break-in run at all. The only reason for the raised speed is to assure there's plenty of oil being thrown off the connecting rods to assure the cam lobes are flooded with lube. The specific speed is irrelevant, as long as the engine isn't revved up enough to start hammering those new rod bearings out of shape. 1800, 2000, 2200, 2500- - - -who cares? A raised RPM initial run does nothing to seat piston rings. That requires about 10 full throttle accelerations from 30 MPH to 50 MPH in high gear, so once the cam gets its run-in, head out on the road for a long straightaway. If your new engine never sees anything but a run stand, maybe you can rig up some kind of chain drive. Good luck steering and stopping!
Jerry
