Is there a certain fabric/material that's optimal for buffing ala the mac method?
IMO the cheap flannel cloth works very well, you can buy rolls of it either online or pick it up from a local shoe repair shop. It'll probably run you a buck or two a pop.
You need to get a horsehair brush if you don't have one yet for your Indy's! Nordstrom Rack has Kiwi horehair brushes for $5.95 - bargain. Buy a couple, Uncle Mac just clarified that you CAN share brushes between shoes as long as they're the same color.
I would not recommend the Kiwi horsehair brushes- they are too small.
There is a guy on ebay (username: coolshoeswalter) selling 6.5" Star horsehair brushes for $7.50 shipped which is a much more useful sized brush.
I personally keep a couple of brushes. One for brushing out dirt and another for buffing. For shell it not be a big issue but for calfskin I think it is more important. Also, being in NYC, my shoes go through a lot of walking and dirt comes with the territory.