hmm....if i were you i might try out a 44cm and then if it doesn't work, swap it with a similar compact-drop in 42cm. never hurts to experiment a little. with craigslist and such you won't lose much by trying a 44 first.

i had 38cm class-bend bars on one bike, and 42cm ergo drops on another, and my shoulders are about 38cm across. i liked the 38cm width way better, as i could tell that 42cm was way too wide. so, i ordered 38cm FSA Omegas for another bike. they felt great and everything, even though i suppose they are 37cm at the hoods.

fast forward to me getting a new road bike, which came stock with 40cm compact drops. they feel noticeably better than the 38cm Omegas, although it's hard to objectively say why. all i know is, now when i ride the Omegas, they feel slightly narrow.

a bit wider bar will allow you to open up your lungs more, be a bit more stable for out-of-saddle riding, etc. but of course, there's a balance point past which a bar just becomes uncomfortably wide. find it!