RR58 longer blade length is a Maltby design standard intended to move the center of gravity further from the hosel.
I was just checking the heads against other irons I have, that do not look 'long'. Must be a visual thing, due to the thin topline of the TS1, as all comparisons seem to be same lengths.
The STi model has an undercut in the cavity, the TS1 does not; doesn't even look like a cavity at all.
