I don't bother with the water at all. I typically find that by the time I run to my transtion area my feet are dry enough to get 90 percent of the sand/gravel off, simply by wiping my feet off on my towel and bending over and quickly dusting the rest off with the free towel ends.
As for getting out of the wetsuit quickly, cover all the bits that tend to get caught with body glide - ankles to calves, wrists to forearms. Practice unzipping as you run toward the transition. If possible try to get your arms out on the way as well. Then get ready to drop on your butt on a grassy bit and if you have wetsuit strippers, they'll help you pull off the lower half. If you don't have stippers, I would still try to take the suit off on a grassy patch prior to getting to transtion area, it's easy to start knocking all that stuff over once you're in amoung the bikes. Especially since you're going to be the first one out of the water and all the bikes will still be there.
One other tip, if your feet get wet on the bike it's worth taking the extra time to change socks before the run. Wet socks are a recipe for huge blisters. It may not stop you on this race but would mess up your training for sure over the week or 2 following.
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2007 Look Dura Ace
2010 Custom Tonic cross with discs, SRAM
2012 Moots YBB 2 x 10 Shimano XTR
2014 Soma B-Side SS