I'd say go with the xanax - zolpidem can get pretty trippy on its own, and on a speed comedown, you could run into some unpleasant hallucinatory synergy, especially with DPH in the mix, despite the low dose. Benzos are a very bad drug to take regularly (still tapering...), but perfect for speed comedowns - and 2 mgs of Xanax = 40mgs valium. Should be more than enough, unless you have a significant tolerance, to put you to sleep, or at least leave you warm and comfortable. Ambien + DPH + benzo + 'phet residue could induce all kinds of weirdness, and in the absence of a pretty high benzo tolerance, you won't need more than 2mgs of xanax. IME, the purer the 'phet (sulphate), the easier the comedown - and you didn't do all that much to begin with. 3 sedatives = overkill, especially with zolpidem in the mix: trippy amnesia with benzos, antihistamines and amphetamine in the mix could turn a minor adventure with sulphate into driving your car into the nearest void.
Even certain benzos on speed can be unpredictable, depending on the benzo - lorazepam and skunk after a few days andnights on sulphate once had me hallucinating a golden Christ-like figure in a loincloth doing bong hits (I could actually see him) and trying to sell me a used car. It caused some amusement when I shouted, in a crowded chillout after-party 'look, I'm Jewish too, and I can't fucking drive, go rip off some Romans.' But lorazepam and triazolam seem to have a particular, hallucinatory effect in cocktails, and I'd been up for about 60 hours on a whole shitload of heavily cut cheap sulphate and a few hits of X here and there: whereas Xanax and valium, in similar situations, always just shut the speed off and let me sleep.
Ah, sweet 1990s...
I can't see 25mgs DPH having any beneficial effects under the circumstances, it'll just confuse your receptors further.
