For
Constantine I there are five issues, which of course are easy to tell apart due to the changing
bust styles:
1) SMANT } laureate
2) SMANT dot } "
3) SMANT } diademed
4) SMANT dot } "
5) SMANT } diademed & draped
I think it's possible that the caesars, maybe
Helena too, are only included in the first four issues.
As you note, there are two pretty clear
bust styles/sizes for the younger caesars: the initial smaller
head with roughly 1:1 head-to-body ratio, replaced in the 3rd issue with a larger
head with more like a 2:1 head-to-body ratio.
Crispus only appears in the first two issues, which is just as well since
his larger
head is more like the later issues!
There is definitely a general trend from fewer to more rows of bricks. The first 2 issues have from 6-9 rows (at least, I've never noted more), while it seems the later ones never have less than 7, and can have a lot more. Certainly there's some overlap in number of rows that can be expected on the 1st two issues and 2nd two issues.
Another stylistic difference is that the 4th (SMANT dot) issue for the caesars sometimes (not always) has a more elaborate
reverse style with a beveled edge "base" for the
campgate and dots or circles in the first row of bricks. This more elaborate
style, once introduced, might be expected to continue into the 5th (SMANT) issue, but I've never seen it (i.e. elaborate
reverse with SMANT issue mark), which suggests that the caesars may not have been included in this final issue.
Ben