That is some crazy timing. It just so happens I ripped the rear wheel off mine last night to measure it. Mine are a different style rim to yours, but I assume the specs would be the same as mine is a SV420 also.
While I'm sure its not 100% exact, I got 194mm from outer lip to outer lip on the rim. I also measured ~ 115mm from the back lip to the mounting face of the rim. Considering zero offset would be 97mm (half of 194mm), that gives the standard rims approx +18 offset to my calculations.
Depending on the size of the tyre you want to run, I reckon a 0 offset rim would be pretty much spot on.
Reason I was measuring mine.... is because I just snagged these for a bargain! They are 265/70/16 Desert Dueler A/T tyres. A smidge smaller then the extremely common 31x10.5 I see people run overseas so hopefully they will fit without to much of an issue.
Will need different rims though, as it will be pretty much rubbing on the shock body with the standard ones.