assuming you mean the master cylinder mount screws ?
they are m6 bolts, and i use 15mm to mount them to the 3/16"ish (.190) aluminum i use to mount them.
they're available at any homo depot, lowes, ace hardware ect.
those current pads actually have some life left to them, you'll be surprised how little more new ones have than whats shown.
you'll pay out the wazoo for pads locally.
i use these, personally and on my kits....
Rear Performance Sintered Brake Pads Kawasaki ZX 14 ZG Suzuki GSXR 1 Set | eBay