Muzz,
Not sure just how much slide travel these new "E" cam bows have but it's probably comparable to their single cam counterpart with respect to limb angle.
I don't see a problem with the slide attachment as you really don't need a whole lot of slide travel to activate a rest that is tied directly to the slide.
Nock travel is excellent so the actual tuning process should be a pretty easy affair.
I have an APA Ultimate twister connected directly to the slide of my Liberty and it works perfectly.......I would bet the Liberty is up there for shortest overall slide travel.

Oh yeah.......here's some more reading material on the Allegiance.
http://www.archerytalk.com/vb/showthread.php?t=131739