I bought several new mainsprings from a respected used parts supplier. The dimensions varied in the distance between the leaves and length of the leaves from the apex.
I traced a spring in 5 spaces per inch quad paper for reference.
Dimensions were measured with dial calipers.
Two springs were measured with "a" and "b" labels.

Can these dimensions be verified as proper fit?
This is in reference to a 1928 Ideal 12 ga.
Thanks Mike