A good 5wt SHOCK oil, not fork oil, is a good choice. I use Bel-Ray HVI, but any high viscosity index oil will work. However, I find all the talk of heavy oils and tank slappers interesting.
The stock SV1000 damper is far too stiff. A steering damper should have almost no resistance at slow, "steering" speeds, yet should stiffen when impacted, "fast speed". I found the stock damper made the bike feel "nervous" in corners, due to the fact that the steering was too stiff to react to my usual small steering inputs as on the other bikes I have. It was like the steering head bearings had been cranked down tight. The bike handles perfect without the damper - no headshakes or anything, and that's with the rear raised ~3/4".
I machined about 0.005" off the OD of the brass "orifice" in the damper, significantly reducing the slow speed resistance while still providing fast impact resistance.
If a bike "requires" a steering damper to stop a weave or headshake, then the bike or rider has an issue, and the damper is being used as a crutch. A steering damper is an emergency device, there for when something out of the ordinary happens - hitting something in the road, grounding out in a corner causing the rear tire to lift and step out, etc.