Hi there, I totally get your fears, when I got the diagnosis they gave me a prescription for 3 times 30 mg a day.
i also thought, what if i dont have mg?
So, I started 10 mg.
A cholinergic crisis is scary, but I dont think you can get it from only 30 mg. Just try it, if you find it too scary try 10 or 20 mg the first time. Ask someone to be with you. Mestinon works fast, so if it is too much, youll know soon enough.
Anywaym Im on 6 x 90 mg now, and still no cholinergic crisis.

Good luck!