I'm the other way around. Because I have arms like an ape and don't like a lot of saddle-to-bar drop, I actually prefer a frame that's a little too big. If I were to put hoods on either of my bikes though, I'd most likely be a little too stretched out with my current stems.

I've found that a 55-56cm top tube and 100-110mm stem is ideal and the extra cm of seat tube on my Gara extended the head tube just enough to get my s-t-b drop right where it should be.

If you were comfortable on your 58cm 722 with a 100mm stem, you'll need a 130mm stem and a lot of seatpost to ride a 55cm Gara and the bar drop will be huge. FWIW, my 58cm 722 is set up with risers and a 90mm stem (which is the only setup I've ever wanted to use on that bike). If I ever put drops on that bike, it would probably suck to ride.