I know you didn't ask me, but I'm running a DHR2 2.3 front, and SS 2.3 rear... on 30mm ID rims.
The SS does spin on loose (over hard) terrain in the climbs. So it's something you'd need to adjust to.
Never had that issue with Mountain Kings 2.4, HR 2 2.3, Shorty 2.3, or DHR 2 2.3 on the rear.
Compared to the HR2 it grips better in the corners, but braking in loose/medium is significantly diminished. Makes up for it in rolling resistance.
Would want to try some of the WT tyres, the IKON, Rock Razors...
Potentially Nobby Nics, only for weight savings... because I'm pretty happy with the DHR2 up front.