So my next project is to start keeping track of Seagate part numbers and how they relate to head compatibility. Obviously the first three of serial is most important to matching, but sometimes you might want to look for a drive with more heads from a higher capacity drive. So I figure it'll be easy enough to track these based on the ones that occasionally do have the right first three, and match all other specs. Seems they really only change the last digit before the hyphen based on capacity.
First set I'll add:
9YN162-XXX - 1Tb
9YN16G-XXX - 1.5Tb
9YN164-XXX - 2Tb
9YN166-XXX - 3Tb
First set I'll add:
9YN162-XXX - 1Tb
9YN16G-XXX - 1.5Tb
9YN164-XXX - 2Tb
9YN166-XXX - 3Tb