If you have an OSMG within reach he would be the first to ask, then I would go to the sources on the web. The speciality stores for screws, nuts, bolts, tools, etc. will get you the correct right screw though. They will measure the dimension of the threading, width of the head, note that it screws in flat with the surface, etc.
since you have the plugs and pedal, all you need is a few yards of good quality two core wire.