Tim, whatever you do, DO NOT COMBINE EVEN AND ODD NUMBERED PRODUCTS! ;)
Just kidding; there are people here who have only done homogenous sets and those who have done mixed sets, as well as mixing brands. The results seem to be uniformly good either way. As regards the run of the two cables, some twist them, some do not. I have tried the Clarity Cable Organic IC with one twist and tried them without the twist, and the difference did not pass my Law of Efficacy. In that case I discerned no difference between twisting them together and not.
Frankly, imo doing the Schroeder Method typically raises the performance, even with moderately priced cables, beyond the best single IC the company can offer.