An engine run-in stand is not the greatest solution either. You cannot put any load on the rings just running in essentially neutral. The SF-902 has an automated test cycle literally called "break-in". I use it all the time. I have never seen anyone on YouTube ever use it or even knows about it. It works like this:
The operator selects the lowest rpm the engine will see I usually select 1900rpm, and the the highest rpm which I like 2400rpm. Then number of seconds per cycle, I like 60 to represent minutes and then I select 5 cycles = 5 minutes. I start the engine hit the start test button and then put about 75-100 ft/lbs of load on the engine. The test cycle will spend 30 seconds dragging the engine down to 1900rpm and 30 seconds reducing load to allow the engine to hit 2400rpm. I leave the console and check timing, water, exhaust temp etc.....After 5 cycles I shut it off for 5 minutes and then repeat all over again for 3 more cycles for 20 minutes total. This loads the rings properly, and I can usually tell if other issues will arise during this process. FWIW, J.Rob