I say get as big of an arch as possible. Of course, you may not be that flexible, but if you sacrifice the arch, you will most likely sacrifice the amount of weight you can potentially move.
pinky fingers on the outer rings, or perhaps a centimeter in from there. you're right that a wider grip will lessen the ROM, but I don't like the idea of lessening ROM that way. the farther out your grip is, the less you can bring your triceps into play, and since the triceps are so important, going wider may decrease your pressing ability. developing a good arch is probably good enough for shortening ROM.
pinky fingers on the outer rings, or perhaps a centimeter in from there. you're right that a wider grip will lessen the ROM, but I don't like the idea of lessening ROM that way. the farther out your grip is, the less you can bring your triceps into play, and since the triceps are so important, going wider may decrease your pressing ability. developing a good arch is probably good enough for shortening ROM.