I’ve also just gone up from 685mm to 710mm for bars and down from 90mm to 70mm on the stem.
Wider bars will move your position on the bike forwards if you stick with the same stem length, so it’s all a bit of a balancing act.
I don’t think I’d want to go any wider than 710mm, so as you’re at 630mm I’d probably give a set of bars somewhere around 670mm – 685mm wide a go.
There are plenty of people selling bars in the classified section, so you should be able to get hold of some bars reasonably cheaply & if you don’t like them, then you should be able to sell them for what you bought them for. I’ve had very good experiences so far buying via the classifieds, so I’d recommend it.