Fry up a slice of your homemade bacon before you smoke it. If it is too salty, soak it in water for awhile, then try it again. You will get a feel for how long to soak it, to get to your desired salt taste based on the recipe you use for curing.
If It's nitrates and nitrites you are concerned about, I recommend EcoCure from The Sausage Maker. It works great and we can't tell the difference between using that or pink curing salt. It's not cheap, but it doesn't take much to do a whole belly. No nitrates or nitrites and no celery derivatives. Check it out.
Other than that, get the best pork you can afford from a reputable source at
Exclaimer.
With all of this, you will know what you have, what went into it, and it will be at your desired salt level.