I've done leak down tests for a lot of years by putting the cylinder being tested at TDC both when hot and later when cold, I do rock the crank a tiny bit, no more than 5 degrees from TDC either way to see if it will seal better by loading the rings both ways
I used to own a airplane, all the annual tests I had done by A&P mechanic always tested each cylinder just above bottom dead center on the power stroke to check the ring and valve seal on all cylinders, I would be ask to grab the prop and spin it towards TDC to load it against the air pressure put into the cylinder by the A&P air compressor
They allowed up to 40 % leakage when cold
I was concerned on my car street motors when they leaked worse than 15%, less on the race motors when warm
As far as my comments on your plugs there are way to much shiny with oil on those plugs for me to keep using without fixing the oil sealing issue first
Visual oil on the spark plugs can and will lead to detonation, especially with NOS
Good luck