Andy,
Yes there is 1" on 1 side and 1 and 1/8" on the other.

The crown race tap of design works like so.

The fork jig length scale will take into account the distance from the front edge of the of the V-block to the center of the dummy axle, all you will simply need to do is subtract whatever you decide you want the crown race offset offset to be, the shaft it's attached to is laser scaled. I chose to go this route because often times I lose my 50mm spacer I am using right now on my current fork jig, and I thought it would be nice to have this measurement always with the jig. It would also be nice to increase the offset from time to time. Once set and the steerer tube is locked down you can move the crown race stop back and out of the way.

Here is a picture explination


Fork Jig Explination by Todd Danger Farr, on Flickr

And here is the laser etched shaft which you subtract. You set it to whatever offset you want and subtract that value


Fork Jig laser scaled shaft by Todd Danger Farr, on Flickr

Hope this helps