Headlight buckets

Can someone here give me some ideas of where to locate some sort of diagram that shows how the headlight buckets are mounted? When I bought the car (1970 Duster) it was equipped with fiberglass fenders, and previous owner had just used the trim rings for the headlights to hold the headlights in place. No obvious way to adjust them. I have a set of the buckets, I just need to know how to mount them.
Thanks much!