Re pads - I had to change the pads on my Dura Ace AX calipers recently. In the absence of the correct pads I cut down some cartridge type pads. You'll find that you can cut the right shape, but will struggle with the thickness of the pads, leaving a gap between the pad and the side of the caliper. I got around this by packing with an appropriately sized piece of metal plate. The other issue with cutting down pads to fit is that the grub screw that secures the originals in place won't have a hole to screw in to on the new pads, easily solved but worth considering.
Also the bolts - one of my calipers was missing the square headed bolt - a hex headed bolt will work but only once the head is filed down to suit - otherwise I found it was too thick and stopped the brakes working properly.