Unless you are very experienced with spices and blending, more than 5 or 6 ingredients and you will be muddying up the flavors of the spices you are using.
Balance is important, each flavor must be balanced in a spice blend, there is no point in adding a spice if you cannot taste it.
You cannot effectively evaluate any rub or sauce without cooking it onto meat, in smoke. Weird stuff happens once you add heat and smoke.
Test out the rub first, if the rub doesn't work, the sauce will not fix it. Then add the sauce ideas, until it complements the rub and meat.
Whip It Off, Chambers!
"perhaps...but then again...maybe not..."