That article refers to general recommendations for all experimental aircraft and dosn't properly frame what you may be doing and what most of us do is build, without varying much from the tried and tested, a Vans RV. There are 10,000 flying and the IO-360/390 w/Andair Fuel Pump is in a lot of airplanes.
I'm not saying that level of testing isn't prudent, it's just that, for example, Lycoming already test run the engine before they shipped it to you and you do a fuel flow test as part of your FISDO requirements for sign-off.
It's easy to get the plane to the required attitude for the fuel flow test but not sure I would tie one to a tree and run it up at break-in settings for an hour, seems like a disaster waiting to happen. Maybe in an engine stand, but again, Lycoming did it for you.
Also the running 1 hour on the ground contradicts Lycoming's own break in procedure and a lot of experienced advice out there that says to run it as little as possible until the first flight and then fly it like you stole it:
Not giving advice, just framing that article against what you are building. Curious what others have to say.