I don't use salt anymore for my salt pulls. I was bloating too much and way too thristy afterwards. I switched to potassium chloride powder and that seems to work just fine. I use it the same as salt. Brownstein or one of Iodine doctors recommended this instead for people with high blood pressure and it's cheap in the powder form.
In terms of a substitute for Epsom Salt I've used nigari for years now. It's potassium chloride and more effective at getting magnesium in transdermally. Plus it's dried from ocean water so contains other minerals. Nigari is used to coagulate the bean milk to make tofu.
There's a couple of sources for it but I buy mine from here
I buy it in 40lb bags of that cost around
$40-50. It will last a long time because you don't need near the amount as Espom salts in a bath to be effective. In fact too much nigari will leave my muscles way too limp.