Brianjeff50 wrote:Any advice on size,
Whatever size you get, you'll end up filling it, there's some law of physics that compels it.
So, I'd work out what you actually need in front of you and easily removable and buy the size that it fits into. From your list, I'd suggest the tools are better off stashed somewhere else on the bike and the waterproof needs a different home (Do you want to be opening the bar bag in the rain, or putting a damp waterproof back in with you valuables?)
I have a 2.7 litre Ortlieb Compact and a 7 litre Vaude Aqua, both probably ten years old, so not the current models, both still functioning fine. I only use the big one if I'm carrying a larger camera and extra lenses, otherwise much prefer the compact which carries everything I need though has no room for a map case. A note on fittings, Ortlieb bags fit Klick Fix (As used by Vaude and Carradice amongst others) but it doesn't work the other way round, Ortlieb brackets only fit Ortlieb bags (EDITED - For confusion, mine.)
All bar bags do have an effect on handling, some riders and some bikes are more sensitive than others, IME I soon get used to it. Unsurprisingly, the compact has the least effect, with just wallet, phone, small camera and any tickets in it, I hardly notice it.