ubolt and spring bolt size

so im about to do a bastard pack on my xj. im adding the main and second leaf from another xj to my pack. my question is does anyone know what size spring bolt and u bolts should i need for the thicker pack?
also where would i go about finding spring clips? all the parts stores around here have the spring bolt but i cant seem to find the clips. should places like oreilly's or napa have them?

I had to go to a spring shop

The u-bolts you'll need should be either a 1/2 x 2-3/4 x 8ish for a dana 35 or 1/2 x 3 x 9ish. That's really assuming the leaf packs are about 2 leaves (1/2 - 3/4") thicker than stock. When in doubt though, measuring is the safest route.

If you hit up ruffstuff they can get you some super nice 5/8" u-bolts and for the center pin I just took my old one off and found a new bolt to fit it. If you are worried about the head of a bolt being too big for your ubolt plate then you can drill it or use an Allen hsad bolt