I have ALWAYS pre-run my engines before final installation. It doesn't take anything elaborate. I used to start engines sitting on an old truck tire. The only precaution is to make sure it doesn't roll over. Done it many times without any issues. Your proposed set-up will work okay too, given a few precautions.

I think it is important to run the engine up to temp a few times before that final install. I check for any leaks, break the cam in, catch any mechanical issues, etc. And I wait until after the pre-run to paint the thing in case something needs unbuttoned.

There is plenty of time to 'seat' the rings after it's up and running in the car. I have never had an issue after install doing it this way.

Of course, this is not the only way to do it. But has ALWAYS worked for me.