Hold up, solar powered meter? That's the real problem. Those things are junk for real work. The light from your headlamp was enough to trick the sensor. You need a proper digital meter with a battery, not some gadget that runs on ambient light. I had a similar one fail because a shop light was too bright. Toss that thing in the trash.

Tough spot, but that's on your scheduling.

My buddy swears by the steel core rods for longer runs. Says they don't kink as easy when you're pushing past insulation.

Saw a post that said colored frits can cool differently... might need to adjust your initial heat to match the base glass. That could prevent hidden stress.

Tape your shoes, solves that spill problem every time.