Great Idea! I have the plug in type that actually shows the spark itself and only shows it in a orange red color and how intense it is, but I will start using this idea using the spark kernel and the width, color and snap side to side on the old plug at .060 as that sounds like a much better idea. I can't tell you how much I appreciate all of your help and knowledge!! I owe you for this one!!Leakdown is like a 5min deal! However, the reason I did not recommend it is compression testing is going to give you more useful info right now. If it does not build proper compression, THEN do leakdown so you can find the windy city.
When I say spark energy tester, I mean this or similar. You stretch the gap to see what it can do. As a tech bit from electrical engineering, the ability of electricity to jump a gap is directly related to the voltage. A coil can typically jump 3-5x the normal plug gap but you stretch it out to see what it can do.
I am NOT saying this is spark right now, but it is on my list until ruled out.
EDIT: In a pinch, grab one of your used but likely good spark plugs and open the gap to about .060". Use it on both sides while out of the cylinder and 'look' at the spark kernel! If one side is fat, blue, and has 'snap', while the other is thin, yellow, and lazy, you have something.