Hey man, I also made a pure to do some low level pking on while im grinding on main etc. My advice would be to stay 50 attack as melee is mainly used for specs on pures as range has a much higher dps until you get to 90+ str.
45 prayer is optimal imo, unless your with a team when smite is useful. Try to keep your offensive stats balanced with each other at all times to have the highest dps across all three styles.
Something like this would be pretty effective
