You are correct, Ric. The KV demand will be influenced by the largest gap in the circuit, as well as the timing of the spark and how much pressure is in the cylinder when it fires. The fuel mix also has a large influence. (lean drives up demand)
Your maximum KV requirements will be experienced under a snap acceleration. At this time, the spark will occur closer to TDC (higher compression) and the mixture will be quite lean for that instant as the engine takes a big gulp.
Never would I expect the KV demand to go anywhere near the max coil output. A stock normally aspirated angine KV demand should be under 25K. For full blown race applications, the demand would be higher under maximum demands.
High energy coils are better able to keep the spark lit as long as the burn is consuming fuel. Higher KV demands shoeten spark time, as there is only so much energy available.
To reliably capture the firing line, which is only a few microseconds, you will need to have the samples maxed out at 32,000 and have less than 100ms on the screen. More time will require the use of the min/max selection which will accumulate passes on the screen to display the max KV.