Well, that didn't take to long.
Here you go:
Piedmont 350 -- 206
Piedmont 150 -- 98
Sweet Cap. 350 / 30 -- 87
Piedmont 460 -- 49
Sweet Cap. 150 / 30 -- 16
Sweet Cap. 350 / 25 -- 10
Sweet Cap. 460 / 30 -- 8
Sweet Cap. 150 / 25 -- 7
Sweet Cap. 460 / 42 os -- 6
Sweet Cap. 150 / 649 -- 3
Sweet Cap. 460 / 25 -- 3
Sweet Cap. 460 / 42 -- 2
Old Mill So. Lg. -- 24
Polar Bear -- 2
The SC150 30 to 25 ratio is about 2:1, which is arguably about right.
Although, the SC350 30 to 25 ratio is almost 9:1, which is probably high.
Basically nothing new or revolutionary.*
However, I feel, even though SC 350/25 backs are common, they are quite rarer than other accepted common backs.
* but, fun, as always