Looking back on the thread there seems to be mention here and there of folks being happy with 1.5 inches (38mm) slack on the centrestand. I did a lot of experimenting today and I tend to agree with this assessment. With the bike on the sidestand and the shock spring preload turned back to minimum I am getting between one eighth and a quarter inch difference. Putting the shock spring up to my usual position of 75% preload I am getting no difference between on or off sidestand. As such I am sticking with 1.5 inches with the bike on the centrestand.
I will second this, and add 1 3/4 is fine too in my book
I've had my bike set at 1 3/4 since the first week i've had it, set on center stand. I always worried it was too loose, but every time i do a reality check i leave it.
During my last check, i had 1 3/4 slack while on centerstand. I dropped it onto the side stand, which compresses the suspension 1/8" more than centerstand, basically nothing (5 clicks from full preload). No change in slack, still 1 3/4.
I then let out the preload completely. The suspension then compressed 1" from centerstand. At this point, the chain wasn't completely tight, but getting there. In my book it was perfect, just enough room to move up and down a little without stress on sprockets/chain/shaft.
Now when i sit on it, i get about 1.5" sag, so it should be even tighter, then add the wifey on the back, you get the picture. 1 1/2 to 1 3/4 should do it, from center stand