Opel Rallier since 1977
I've never used a dwell meter on these and used to rev the stock system past 8k RPM all the time; never a misfire. IMHO, 4 cylinders are not all that critical compared to V8's; relatively speaking, you have double the time to charge the coil's magnetic field between firings. Once you are past the minimum needed dwell angle to adequately charge the coil, the remaining dwell time is not of any use.Adjusted the points with the correct 0.016'' feeler gauge between the points. (I have the 1975 type FI distributor), which I have done many times before, but this time I didn't rely on the feel gauge alone, but also used a dwell meter, and surprise surprise 0.016'' gave me a steady reading of 43 degrees, but using a 0.015'' gave me spot and steady 50 degrees dwell.
I must (shamefully) admit that I have always relied on the feeler gauge alone, and never used a dwell meter to actually check if my adjustment was spot on..- let me just say that won't happen again.