I think "favorite drug combos" means you've tried it before, probably many times, and after lengthy personal deliberation, concluded it's your favorite.
Mixing 6mg of Xanax with any downer is a bad idea, even if you're a "benzo veteran". I can be a bourbon veteran, but I can't drink a fifth and expect good things from adding brand-new-to-me meds, especially ones known for overdose risk all by themselves. 60mg is a lot of oxycodone at once, too. Too much if you're "not sure".
Why wouldn't you just try the oxycodone by itself? Half that dose, actually?