I rode clips and straps for a few years fixed. Clips need to be slightly bigger than you need otherwise the ends of your toes will touch and this will wear your shoes and also become painful after a while. Single straps are fine, good quality leather best, unless you are track-sprinting, put a twist where they go through the underside of the pedal to keep them in place.
But ... spds are much better in all ways, also diminishes toe overlap.
I rode clips and straps for a few years fixed. Clips need to be slightly bigger than you need otherwise the ends of your toes will touch and this will wear your shoes and also become painful after a while. Single straps are fine, good quality leather best, unless you are track-sprinting, put a twist where they go through the underside of the pedal to keep them in place.
But ... spds are much better in all ways, also diminishes toe overlap.