A cap head (Allen) bolt may work. You want to check that the head is close to the size hole in the spring perch, a slip fit. If not the springs can shift and change alignment during use. When I bought OME springs the pins were to small and I made bushings that kept the springs properly located on the perch pads.
Toe in wise, usually 1/8" works at least it does for me. You want the least amount of toe-in that keeps it running straight. Excessive toe-in speeds up tire wear.