That makes sense, however I did not mean to imply that my shatter was inferior or that shatter in general is inherently poor quality, it's just lower grade hence the typical bargain prices. I suppose my theory was based on the fact that comparable quantities of different forms of concentrates leave varying levels of residue behind. My observation thus far has been that shatter leaves behind the most by far. It takes at least 2 Qtips with a dab of shatter vs 1 Q tip with a dab of sugar wax for instance. Diamonds barely leave behind anything in my experience, just a little grey residue on the Qtip.
That said, I believe I was able to trace back the cause of the residue that is building up only in the front half of the bottom of the banger. I'm almost certain this is because I'm leaning backwards when I use the RiO, which causes the oil to slightly pool to the back and leave the front pretty much bare. When I tip it back forward I'm guessing the oil shifts back over onto the hotter surface of the bare nail and burns, which explains some funky flavors sometimes too. Also, as lucky as I got with my RiO being so well centered, it still favors the front of the core ever so slightly so more heat is technically going towards to front of the bowl too which I need to compensate for. I'm going to test this theory and make sure I lean forward more or at least not backward when using and if no more residue then it just might be the cause.
I'm pretty happy with the stock core banger but I am getting interested in procuring another, at least as a backup in case. Really curious about these spinner caps and terp pearls just not sure if it's really worth the extra money and trouble. The idea of "self stirring" is pretty tempting but I just feel ambivalent about the whole thing, especially not being certain it will properly align with the RiO...