I HAVE BEATEN DARKRAI 175!
It took me three tries, though... First run I went in with m-ray, darkrai itself, machamp, and xerneas. The combos did not come and machamp must have been asleep through the whole thing... not a single RT activation >.< Second try I swapped xerneas for genesect, using Crowd Control for more damage (even though I know it's been majorly nerfed). Got darkrai to less than 10k health before running out of moves.
Third try, took in the same team but gave machamp a pep talk (yelled at my console for several minutes; thankfully I was the only one home!) and that seemed to have woken it up. Crowd Control and Risk Taker were activating left and right, and m-ray must have decided not to push its luck with me because it was comboing beautifully. Once darkrai started disrupting itself in, I started getting even more combos and took it down with 4 moves remaining.
And that is it. I am done with darkrai. There's no way I'd be able to beat the higher health at stage 200, not with my current team and still-mostly-uninvested machamp. I got 7 speedups squirreled away for when I eventually get to mega ttar's stage (I want to start pushing ahead again once I rebuild my depleted coin stash). For the moment I'm back in the safari; I still need winkaphy and staryu pops up frequently. At least I can consistently get 600 coins from staryu, unlike meowth (which is still doing its best to screw me out of as many coins as it can).