Ratchet, can I ask how much clearance you have between the rear tyre and the ground when on the centre stand ?
If it is more than about 5mm I would suggest you adjust the rear ride height instead of the preload.
Mine was set to around 30mm when I brought it, and the stands would touch down on fairly mild lean angles at very sedate speeds.
I adjusted the ride height and all is now well - I run out of tyre before touching down now, unless there is a bump mid corner of course
Just be aware that the bike will lean over a lot more on the side stand...
Hope that helps.