Stuck with the flats and definitely the right choice. Transitions were a breeze. Must have saved at least 90 seconds. Not sure the flats made much difference to my cycling anyway. Average speed with flats, normal helmet and trainers was 37kph @ 260W which is in around what I would expect in full aero kit! Makes me wonder if its worth doing the same for a sprint tri??
I somehow managed to 'squeeze in' an extra lap on the first bike section but ran back into 2nd place anyway. It wasn't a big turnout.. Don't think I would have caught the winner had I been able to count.
I've been using a fixed gear bike with grippy platforms and haven't slipped off yet (except at 150rpm.. thankfully I've got brakes on the bike! ) I'd be happy enough to go without unless there was significant speed to be gained.