Two very simple things I used to check ignition.
I cut thru the threads of 2 old sparkplugs (about halfway back) and broke off the insulator leaving the post sticking out, after cleaning things up I put the plugs in the wires for cyl 2 and 3 and measure the total resistance of wires and coil, by attaching the multimeter to the post sticking out of the plug. should b about 20k ohms. Same thing for cylinders 1 and 4

The other thing is to pull all 4 plugs, reattach them to the wires and connect the threaded section of each plug togather with a length of bare solid copper wire. It does not need to connect to the engine just to each other. Crank the enginge there should be a nice fat blue spark.

Sorry no pictures

Seem like a real simple thing to try. I have always used a screw driver in the wire and check for the blue spark when turning over. Never measured the coils that way. Sounds pretty good.

It took me quite a while to figure out that the screw driver in the spark plug boot next to the engine trick only works if there is a good spark plug installed on the other side of the same coil

that is true my friend. I always keep a known good plug around. But that is true only if your coil is feeding two plugs. If there is only one plug per coil then it's a reasonable test.