Running the engine to 100 degrees on a test rig doesn't mean that you are going to have it all set up correctly when you install the engine in the car. Why not buy a cooling system pressure tester and an oil pressure tester and do it with the engine in the car.
If you do set up a rig, then have a good sized rotor welded to the tailshaft and use a whole gearbox, not just the bellhousing. That way you can set up a basic breaking system and use a 1m bar to crank pressure down to load the engine.
Personally I don't see the point as you have to test everything all over again because it's being removed from the rig and installed in the car. If you were building a lot if engines and needed to run them in, I could understand, but for a once off, it seems like a lot of work.