Excuse me while I ramble a bit...
I do find certain video arcade type games helpful for reflexes, true enough, but the biggest problem I found at least for me is insomnia. Along with just physical reflexes, I think another very important aspect of CL Stunt is concentration. I've found that nothing screws up my reflexes & concentration like a solid week of 4 hr night sleep times. On an unusually good week, if I get 6 or 7hrs a night, I find the planes so much easier to fly it's almost like cheating (in comparison).
You know, when you can actually feel like you are not just banging a corner as a single event, but actually controlling the entry & exit of the corners, and seeing the shape etc of the whole maneuver as you fly it, making corrections as you go. That's when your really on in both reflex and concentration, and you can feel it.
Unfortunately, I'd bet many of us at contests are pretty well road weary. This is where arriving a day early can help, but even then, if you don't like the mattress, etc. and dont get good quality sack time in the hotel you can still be off your game. This is probably the biggest home field advantage, aside from familiarity with the flying site. I think the one saving grace is the body's ability to generate and use adrenalin to hype us up a bit.
This has been something I've been working on for a while, and am glad to see the topic here. I look forward to seeing others responses and how they deal with the situation.
EricV