I use wax based bullet lubricant sticks (have tons of it from experiments) and rub the ends to get a solid coating. Shellac is really good, paint is better than nothing. 2.5" for a longrifle unless you're building one of those Colonial oars with a huge cheek rest, a lot of cast off, and a large barrel that requires 2" or more across the cheeks. I like more than 8" wide, 10" minimum so you can dodge sapwood, bark inclusions, bug holes, knots, and other things that pop up when you start cutting into it. Along those lines, I also like to leave about an inch of wood outside the blank line from lock to toe and lock to heel above the comb, this allows a couple inches of fore-aft relocation should you run into something unexpected with the band saw.