I used the De Soto speedtube all summer when I was living in Iowa. Most of the races around there are only wetsuit legal because they find a cold part on the lake to measure. It works great, you’re still cool but getting a lot of the wetsuit benefit still.

In a case like this, I'd go with a pair of the Roka swim shorts. I have a pair that was given to me but i've never even worn them in the pool b/c i would just feel weird wearing them, plus everyone would be asking about them since I’m always just wear a Speedo brief. I'll use the pull buoy sure, since it is an established piece of swim training equipment, just like the kick-board, but i'm not wearing any "cheater shorts" in the pool. A race like this with relatively warm water would be the perfect time for these shorts though. :)