"Tony - no need for a load on
"Tony - no need for a load on the motor.
As far as running it out of the boat.....unless you have a running-stand, with a full set of external guages (tach, temp, oil pressure, etc.) and good cooling delivery, the very most I'd consider doing is simply turning it over to confirm that it runs.
In addition, the cam break-in process should really begin with the first firing. It's okay to fire it up briefly, a couple of times, to tweak the carb, get it to idle, etc. but.....once you "officially" get it fired up and running, you should really be prepared to run it straight through the 20-30 minute break-in period.
Timing and fine tuning should come after the cam break-in.
Make sure you use a good race or "break in" oil that's loaded with zinc.
Good luck."