Welcome to ECF and really at lower resistances do NOT use high nic salt or you will o/d yourself.
Nicotine OD is not fun, Try starting out low like 3 or 6 mg or whatever you are using in freebase. Salts aren't different (that much) other than less throat hit which I'd imagine you aren't getting anyway.
For high MG nicotine you need an entirely different setup and way of vaping. It has many names but I go by what I learned first MTL or mouth to lung, you don't inhale as much vapor per puff. Etc. More like smoking a cigarette.
Anna