Hello. Well try them different next time. I don't USUALLY use a mop or even a rub for that matter. Just S&P. Maybe cayenne pepper instead of black. If not that way just try your rub without a mop. Option 3 is an easy to make mop I sometimes use:
400 ml veg. oil
300ml vinegar, white, wine, cider, your choice; I have not tried malt.
500ml lager, I would guess stout would work also. You may find that with stout you need to up the spices
1/2 medium onion sliced
1/4 teaspoon dry mustard
I/2 teaspoon paprika, use mild or hot, your choice
Garlic granules. use your judgement as to your tastes. I use a scant 1/8 teaspoon
Salt and pepper to taste
Throw it all in a saucepan over medium heat. Stir well. Bring to boil. Reduce heat and simmer until onions become tender. Good to GO!
Keep Smokin!
Danny