The most course hair I ever removed belonged to a transgirl, but wasnt on her face. It was on the outside rim of her ear. She had several thick black hairs as thich as coathanger wire, with bulbous hair roots that were posatively huge and looked like ball bearings under the skin. I went at tehm with much more energy with blend, and spread the treatment around the perimeter of the follicle. Easily 4-5 times the amount of energy one would use on a normal follicle.I could not believe the size of these hairs which looked like spikes growing out of her ear.
There was no permanent damage ( except to the dead hair) and the client did not use any anesthetic nor was pain an issue for them.
When you did your test you felt a smallish snap then the hair was removed ( without traction or pulling I assume? ) it slid out. A Thicker hair might take more than one pulse but essentially the same thing. The pain does “build up” after a while, but thick or thin, wont make that much of a difference as to pain levels. Area treated will make a huge difference. Upper lip or under the nose, neck, and jawline, the pain can feel a little more . I often will let clients feel a couple insertions on the center neck, as this is a particularly painful spot and it gives them the opportunity to consider lidocaine cream when treating there. What a lot of electrologists will do is pick a couple hairs on each area and I think this is a more straitforward approach. But essentially it wont make that much of a difference except as to area to be treated.
As to cleanliness, from your description there are some legitiate causes for concern I think.
Seana