2nd the call that having a 14cm stem seems like your Road bike is too small for you. Going smaller on a track would make it worse as on the whole most bikes tend to be 'square', where the ST and TT are similar lengths. So you're top tube would shrink further.

The rule about 'em being 1cm smaller is just a guide. Both TT and ST lengths are really important for comfortable fit and handling.

One option is to try before you buy, if you can. Most Velodromes have beginner sessions and rental bikes. That way you can try a few different sizings out before putting down any cash. Rental rates are very cheap and the instructors can normally offer excellent advice as to sizing, gearing, equipment etc.