I've found myself in the 11 and 12 so rarely in races that I'm considering going to a 13-25. No, I'm definitely not a junior.
Has anyone used this setup in road races and how did you find it performed?
Sure. When I raced in the mid to late 80s I used a 13-24. That and 13-21 or 13-23 were the common cassettes. 52/42, 52/39 and 53/39 were the chainrings commonly in use. 12t cogs were for fast p/1/2s and poseurs who wanted to look like them.
i use 13-26 always, probably switching to 13-29 for 2012 which is what I raced a few years back also.
i just did this - 50x13 @ 120rpm is 36mph (seems low to me, i thought more like 38?).
i have no worries about getting dropped on the downhill of any hilly races. the more difficult is a race with a long, not that steep hill but you just have to either tuck or get on someones wheel or maybe burst a little.