I have Salsa Short 'n Shallow bars as well. I don't know how narrow they are, but I know my bars look tiny compared to everyone else. I can't recall having arm pains, my shoulders and arms feel nice and relaxed on my bike. Yellow is right, I can't imagine putting anything other than a computer on my bars. It already seems like such a tiny space between the brake hoods.
If your new Salsa bars have the ergo bump you are lucky! Once I figured out it was there riding in the drop is so comfortable.
Amanda
2011 Specialized Epic Comp 29er | Specialized Phenom | "Marie Laveau"
2007 Cannondale Synapse Carbon Road | Selle Italia Lady Gel Flow | "Miranda"
You don't have to be great to get started, but you do have to get started to be great. -Lee J. Colan