Yay for Beetles.
I decided to adjust my valves (I even bought a new feeler gauge). The #1 exhaust lost adjustment immediately, in the distance from my carport to the street. So I put it up on the ramps and readjusted and tightened it.
I took the recycling to the Central Processing Facility in Glenwood (2-3 miles) and it happened again. But this time it was the #1 intake.
I ran both lock-nuts over a flat file and reinstalled them, and since then I've made a run upriver.
I'll check them again soon-ish and file the other three cylinder's lock nuts. Out of pocket six bucks for the feeler gauge, that's about all the expense I can handle.