Something finally worked for me
I have been dealing with BFS for 16 years. Nothing seemed to help, although the day after alcohol or before a rainshower my symptoms were much worse.
Then I started propranolol.
This is a beta blocker and is used commonly for social anxiety or performance anxiety. I initially used it for interviews, but I incidentally noted something strange. A few hours after the dose, I was no longer experiencing fasciculations.
I hypothesize that my symptoms are driven by my high sympathetic drive. I am type A and can be tightly-wound when things in life are not under control. Thus the propranolol is helpful because it reduces the sympathetic tone enough to mitigate my symptoms.