You've taken on a project that is interesting and worthwhile if that's where your curiosity and interest lies. You can wash out the salt when you start tanning. I've tanned several coyotes and a good number of other hides and because of that, now send hides I want tanned to a tannery. I know better how to prep a hide etc. because I went through the process of tanning myself and am glad that I learned how to do it. Most of mine turned out pretty nice though I never achieved as high quality as a commercial tannery, and didn't expect to.
IME the most critical factor is getting the hide fleshed perfectly. You can't leave ANY of the membrane on the inside of the hide, and it is tough to get off or even to see in places, especially on the head of the animal. I assume you know to turn the ears and split the lips, to allow tanning solution/chemicals into those areas. Otherwise the lips and ears will gradually disintegrate and fall off of the otherwise tanned skin. Ditto for splitting the tail to the tip.
It is very hard to get a soft, supple hide by home tanning means.
