tttaylorrr, As a new guy here, Thank You for posting your experience, and I'm sorry for the loss of your snakes.
That is a terrible thing to go through, but by posting your experience, I as well as others can be aware of the dangers of PAM.
I believe one of the salt based products you mentioned is this.....
https://www.chewy.com/natural-chemis...pray/dp/132115
I am going thru the "mite thing" right now, with 2 baby snakes I read about PAM and it was a great mite eliminator but the use of it could be really hard on the snakes.
I chose to use the Frontline, that Bogertophis and you mentioned, and was thinking about adding PAM if needed but will now avoid it.