Starter battery cable posts nut sizes???

I installed a Chrysler mini starter and the two studs appear to be metric. I got an 8mm x 1.25 tread to fit the larger post but am having an awful time with the small post on the starter. Can anybody here help me out with these nuts. They were not on the starter when I got it. Where can I get an assortment of these for future problems that may arise? But I want some good nuts with good tolerance and not cheap Chinese crap?? HELP????? Also looking for the correct screws to fasten the voltage relay?? Seems all I have is too loose? Are these just hex head self tapping? My better judgment tells me the thread and pitch is special?? Where do I get them at????