Misfire at cruise, popping/afterfire at 3000RPM

When I got to #4 and found the leak, I backed up the crank to see any difference, and then moved forward. The best I could see was 85% leakage between cylinders 8 and 4, and between 4 and 3.
I don't understand this between business.
Nor is it possible to "back up the crank" with pressure in the chamber unless you have a really long bar, and then you cannot go very far until your bar hits something.
So you are looking at EIGHT different TDC-pressure tests, with each done at TDC-compression. There is no between 8 and 4 business; nor between 4 and 3; nor between anything.
To do a LD test, each piston in turn must be at TDC on it's specific compression stroke.
If your engine had the leakage you are reporting.......... it would not even start.