Misfiring issue

First question is, what is your definition of "skipping?"

What is your guess, missing (ignition?)

Is it possible you have a valve spring/ lifter pump-up / other valve train issue, and are floating some valves?

and WHAT DO the plugs look like?

I don't know why you say "supposed to bump to 780?) A 750 DP should be fine for now, at least until you get this straight.

How 'bout the ignition? Any chance the ignition is not getting adequate power? It could be something as simple as a bad coil, etc.