Too long in brine or too high of salt content in solution, plus added salts in the rub and sauce are the most likely reasons for being too salty. Never use added salts in rub or any other treatmentments when using a brine or brine/cure. Too long of brining time can also result in mushy meats, in some cases.
Being too dry is generally attributed to being over-cooked, with some causes being preperation before cooking....you can't cook meats by time, even if a recipe calls for it. The recipe was likely written by someone who used a different cooker than you have, and uses it often enough to know it very well. Temps with grills can only be estimated by holding the palm of your hand above the grate, viewing the flame of a gas grill burner or viewing the coal-bed in a charcoal grill, but the hand-hold is generally the best approach.
With most cuts of small meat (excluding chicken), I use a very hot grill...somewhere in the neighborhood of 700* grate temp. This will give a nice sear by the time it's ready to flip. I only flip the meat one time...I check color byslightlylifting the edge(s) so as to not dump those juices over the side. If it's not seared to my liking, I give it another minute and take another look before you flip. I sear over the hottest area of the grill I can find, then after flipping it over and searing the opposite side, if I find the meat seared too quickly (not often the case) I can simply move it to a cooler area of the grill (or warming rack) to finish to my desired temp.
Being tough is likely from over-cooking as well. With the addition of sauce, you won't have any reference as too how done they really are. Maybe the KISS method would be in order. Sounds like alot going on, many flavor and appearance changing processes, and it's too easy to over-cook even without all that going on.
I consider chops to be more difficult to cook than cut-up chicken, as they are generally too thin to probe for internal temps, so I cook by look and feel. I like to see a small puddle of juices formed on top before I flip the first time, then allow the juices to puddle again before removing from heat. You can make a small slit into the meat beofre removing for a quick look inside at color. Let them rest a couple minutes before cutting into the chop to redistribute thejuices as the meat begins to cool. If done to medium well (160* minimum for pork), they should be just slightly pink and loaded with juices.
At any rate, I never go by time when cooking meats, regardless of who says that's the way they did it...it just doesn't work for me.