I don't see any problem with what you are doing. The spit patch, as long as you don't over do it, will pull out the residue between shots, and that helps the Ballistol lube the metal of the bore for the next shot. You have to use the right size, and designed cleaning jag with your " Spit Patch", so that you are pulling the crud out, and not pushing it down the barrel toward your breech.
I use Flannel, Cotton, Cleaning patches. My cleaning jag is .030" smaller in diameter for the first band than my bore diameter. The next band back is .010" smaller than the first, and the third band is another .010" smaller yet. This allows the patch to slide over the lands as you push the patch down the barrel, but blouse out, where its grabbed by the grooves in the jag, to wedge the cotton fabric in the grooves of the barrel, and pull out all the crud. Spit makes a fine "solvent" for this purpose.
I do NOT recommend spit as a patch lubricant during a hunt. Spit dries out, and it also increases the change that the barrel will rust where the spit patch contacts the barrel. I LEARNED this lesson the hard way, BTW. If you are concerned about Ballistol spoiling your powder charge during a long day's hunt, use an Over powder Wad or a filler of some kind to separate the powder from the Ballistol lubed patch. Something as convenient as another DRY patch pushed down onto the powder before seating the PRB will often be enough of a barrier to eliminate the problem. I have been using Corn meal as a filler, and Walter's Fiber Wads as an OP wad in my .50 alternately to see which works better. I also have a hornet's nest to try as a filler material.
Because of the relatively high humdity we have here in the Corn Belt, I began running a drying patch down my barrel after I ran a spit patch down to pull out the crud. Only when its below freezing, and the relative humidity is very low, here, can I skip this step without concern. MY trying OP wads, and fillers began as attempt to find another answer to this two-patch cleaning technique. The hugh humidity is particularly a problem when loading smoothbores, I found.