Jase. The first few moments of running are the most critical for a newly built engine. Every moving part needs to have a lick of lube, makes sense and even if the motor just goes back into store the machined parts are protected from corrosion.
Bit late now but if the oil pump is off, prime the timing bush, crank and big ends by pressure fed oil into the oil gallery. Raise the ball valve on the pick up pipe and fill the scavenge side with oil as well by pumping oil into the ball valve housing. If the timing side is assembled, remove the PRV and pump oil to the timing bush etc from there. The oil pump can be primed before the oil tank goes back on or on assembly.
Oil in the bores will aid initial sealing and will soon be burnt off. The critical part of the running in process is to ensure all parts continue to be lubricated adequately to prevent seizure. How you Vary the speed, load, duration etc is subjective and there are varied opinions as you can see.
Don't forget to clean out the oil tank and oil lines, and a check of what's in the sump after a few miles is a wise precaution. I would consider 50 miles to be OK for a check, but if all in order, a bit early to change the oil.
As for that cursed engine plate, it's all a matter of technique. Having the lump down to basics, cases, crank, pistons, gearbox all helps and it's a matter of holding the loose mounting plate in place on the engine and almost diving the unit down and then to swing upwards at the front into position with a final sideways twist at the rear to locate the gearbox mounts as you rattle the mounting plate to fit.
Those folks with S/A bikes can laugh now, those engine plate gymnastics only apply to Plunger Frame Semi Unit Models.
Swarfy.