What Allen said.
However, since you have a deal...
Focus pulling is often difficult to do hands-on with still photography lenses. So, just make the best of it and ensure that the shots you need with racked focus can actually be performed. If you don't have breathing issues, then it's all about the hand on the gear. Last minute shooting on caffeine overload doesn't improve racking for noobs... or cam geezers for that matter. Take your measurements, make your marks, and take your shots (and chances). You'll do it anyway, it's just easier if you de-couple the force from the lens.
Whether or not you need a box depends on the lighting. For many shots, you do. It's all about the lighting and camera position. Try to visualize any possible problems in advance and alter the plan if needed. Otherwise: cardboard, black gaffers tape, and black foil make great raw material for matte boxes and french flags. You did budget for gaffers tape and foil, neh? If not - make it so!
