The reg is more important than the bottle, but for low-flow use like airsoft frankly most are fine. I buy/have bought Ninja and Guerrilla (mostly because Ninja is impossible to find here) and fit Ninja Pro V2 tank regs to them as the Myth G3 isn't quite as good. Again, I should stress this doesn't matter much for electric solenoids or converted GBBRs. Tank regs and flow really only matter in super high RoF builds or something like a Daytona Gun, Escort or Sun Project.
Guerrilla make a decent 13ci bottles, and their tank reg is pretty reliable with well machined threads that aren't going to damage your ASA. I'd just stick with them for ease. Two weeks ago I'd have told you to look at somewhere like HPAirsoft or various EU companies for a good price, but I'm not sure whether that's cost effective anymore.