Those are some really good ideas on the problem and I as well have traveled that way. I actually went ahead and was able to replicate the problem by unhooking some of the grounding wires.
Cylinders 1/5 always run strong. 2/6, 3/7 are particularly consistent in missing and 4/8 do it sometime.
I made my own grounding wire, bolted it on top of the current wires attached to the throttle linakge on the w116 and attached it to the fire wall. No problems for 2 days now. If that is not the problem, I will be replacing the distibutor and the trigger points as one unit and then I will seek a new harness.
Thanks for all your help, I'll keep you updated.