Nicotine salts and caffeine — headache combo?

Thread preset 91/100 for portal simulate-flow. Adult (21+) personal use on a refillable MTL pod — not a review unit.

Current setup: 50/50 nic salt, stock coil, desk storage upright. I track fill dates so troubleshooting stays honest.

This week I am stuck on: Nicotine salts and caffeine — headache combo? Before I buy more gear I want the boring fix that usually works.

If you solved this, what did you change first — coil, nic strength, priming time, storage, or draw style?