I get tremors too, especially in my hands but I suspect I may have a thyroid problem that is still in the middle of being diagnosed. I have all the symptoms (as well as it runs in the women in my family), but my numbers are also normal. It's a bit comforting to see others are having similar thyroid symptoms, I'm not alone.

As for Mestinon, when I took a trial (twice) with it, I did not react well to it. I felt shakey on my feet that I almost fell at work (and I don't fall from MG), was heavy, my speech was much worse than without it, my legs (thighs) twitched so bad, that you could see my legs twitching and trembling through my jeans. I also felt it in my jaw which was scary because at some moments (like when I was eating) I thought I couldn't open my mouth. Then it wore off once the mestinon left my system, until my next pill. My side effects were really sever so they took me off it immediately (I don't even think I was up to a full dose a day and I was having these things). If it increases with your doses maybe speak with your doctor.