i wouldent use them in your rear maggy either, i had some pro bolt ones from tarty and one snapped off whilst doing a tapp, i really dont think there up to the stress thats upon a rear brake, let alone a disc rotor!
get lighter pedals, wellgo mag pedals with ti axels weigh 150g each, that saves nearly a pound over standard pedals , you could run a smaller gear ratio, (16:14) then you would have less chain, and less teeth, less weight
not big enough i dont think, we should go down to buthiers without koxx, i really dont thin there is anywhere big enough in the uk, or anywhere that compares to it