Thanks, by leading edge i mean which way should a disc be passing the pads. the e-scooter they were attached to was so poorly built (and in bits when i got it) that i couldn't trust they were installed correctly anyway. So that is backwards from what i expecting, but it make sense, the adjustment knobs (knurled thingies on the left and right of each caliper) bring the trailing edge of the pads closer to the disc, alright some brackets and welding to do.

and probably even more after i discover these don't work at all and i give in a buy something else. if it worth doing at all, might as well do it twice...