Looking good, Chris -- keep assembling bits outside the chassis, it really helps to test-fit outside to check clearances.
If you can stick with the Dakota fork, it'll save you some heavier fabrication effort. The cross-over style fork is pretty easy to work with in adjusting everything front-to-rear (either, as necessary) by setting up an adjustable pivot on one end and an adjustable linkage on the slave side. A single-sided fork is pretty easy, as well, but the mechanical advantage is just easier to set where you want with a cross-over fork.
If you're running into issues with too short a collar, head on down to the parts store and look at throwout bearings for early 70's Muncie-style gearboxes, there are several different lengths that should fit your input retainer OD. McLeod Industries has an adjustable one that I use, but it ain't cheap. Novak has a pretty good website of issues to consider when setting up the clutch, but it has some errors, as well. A good overview on what to think of, though...
http://www.novak-adapt.com/knowledge/clutches_etc.htm At worst, you could turn down the input retainer OD -- or sleeve it up.
Post up as you encounter challenges with the alignment setup, and I'll help if necessary. My basic advice is that EVERYTHING is adjustable (flywheel, pilot, throwout, fork, linkage), and you can synch individual parts to make your system work... the trick is taking a system approach to get the small throw you need at the firction plate inside the clutch pressure plate, and keep the rest of the linkage from binding /interfering with itself or adjacent bits. Doing a full set-up outside the car and checking air gap and all before you bolt it in will help, as noted above.
I *dig* that you are creating your own solution as you go. You've done your research and I'm stoked to watch it come together. Nice work! <img src="/forums/images/graemlins/kewl.gif" alt="" />
Randii