Hi Big Ir!
I have tried many recipes with pork butt. The biggest problem you have is the roast is so large that no flavor gets into the inside meat. That is why the rub you use on your butt is the least important aspect....it simply doesn't penetrate.
Always remember, rubs and marinades penetrate a maximum of 5mm...that's less than 1/4"..that ain't much. So, not much flavor inside.
Now, this can be solved in a couple of ways.....
1). Score your butts very deeply. The scoring should be done all the way to the bone and in several places. Then sprinkle your rub on...you have much more surface area in this case. You may need to tie the butt back together again. Also, your butt will cook much quicker when scored like this.
2). Inject the solution inside the butt. This is the best way to get flavor to the inside meat. You should try to inject an all-liquid solution if possible and there can be no large chunks....they will clog the needle. The problem with adding a solid rub to the liquid injection is, the rub will not dissolve so the meat is streaked with your rub. This may cause discoloration and varying intensities of flavor....neither may be good.
I like to do my jerk pork with either tenderloins or chops...much thinner cuts of meat.
