Nodal Point for Canon 30D and Tokina 12-24mm lens

The maximum distance that I can set on the upper arm is 107mm. Fortunately 107mm seems like it may be the nodal point for my Canon 30D and Tokina 12-24mm lens. I'd feel more comfortable though if I could test it out at a distance greater than 107mm to confirm. So, I plan to get the T extension, but do any of you have the correct number for this combination?

I see tokina 12-24mm in the database but all on Nikon DSLRs
http://nodalninja.com/nodal_ninja_3_..._settings.html

any Nikon users who have the lens can do the calculation and measure the NPP relative to features on the lens.


nick