Tuneboy adjustment to rectify clock with darkside on

Both Owl, rocketuk and myself (and perds?) are running toyo 235 darkside tyre. I want to adjust the settings in tuneboy to sort out the clock accuracy.

Can anyone help?

Owl was kind enough to send me his tune and I am running a 245 Goodyear. The only adjustments that I made to his tune was I changed (in tune constants) wheel speed to 3248 and the speed limit to 300.
The right way to do it is circumfrence of stock metz vs. darkside and adjust wheel speed until the % makes sense. Hope that helps.