I use 44cm after using 42cm most of my life (due to them being stock on most bikes I bought). When I got fitted for a bike last year, my shoulder width measurement indicated that I should be using 44’s – and when I tried them out it was a revelation. So much more comfortable. No more hand numbness. No more shoulder pain. Couldn’t believe 2cm made that much of a difference.
I understand there is an aero penalty…but consider the following:
- I am very rarely off the front in the races I do. When in a group, there is no aero benefit.
- When I ride solo, I’m training or just plain riding, so the aero drag is fine. I’m out there to push watts, not maximize speed.
- The aforementioned comfort factor. Most of my rides and races are in the 2+ hour range…and my A race is 4 hours-ish. Over that duration, I believe comfortable is faster.
Most folks on this board seem to really push the boundaries of marginal gains in aero benefit – and for a TT bike I completely agree, no argument there. But a great fitting bike this manages the balance of speed + comfort is a truly sublime ride. And at the end of the day, I believe it’s faster.
It’s kind of like a full suspension XC mountain bike. Is a hardtail technically lighter and faster? Yes it is. But you’ll likely go faster over longer duration on a full sus rig (as noted several times on the podcast) because you won’t be as beat up, and you’ll have watts to spare that you won’t have burned by trying to remedy a stiff back, sore shoulders and a red ass 
Good luck!
PS - If you haven’t checked out the Thomson carbon bars, I can’t recommend them highly enough. Featherweight and ergonomic. I ditched a really expensive set of Enve aero road bars for them, and haven’t looked back. Legitimately sublime. I’m going to ride my bike now…all this talk has made me miss the road 