pilots that fly ovals normaly turn at 30 degrees throughout while those who favour squares fly 15 degree banked turns in my experience.
Its not just the amount of time you spend blind that may be the deciding factor in getting close to another a/c in the circuit. its also your standard of lookout and ability to listen out and form a mental picture of what is going on. with four in an oval you should know where everyone is.
the square circuit non discipline i have seen means, get as many in the circuit that want to fit in and make any sort of pattern you feel happy with and turn final at any distance.
get three flying schools in a circuit and you will have 3 different patterns!