Since you're dealing with highly reflective surfaces, I'd suggest experimenting with your light source(s)--try some form of diffused lighting. Good, full-coin, sharp, high resolution, large(r) photos would really help. Thanks.
On the 1960-D The small over large dates, have something to look at first to determine if they die was hubbed with the two different styles on the die. Note the difference in size of the zero on this small date and the one with the overdate:
The first thing to check out is the zero on the date. That digit is huge on the DDO and there is also a RPM on this one.