Ryan,
A 36" bar is common, but with the size of timber getting smaller each year I cut most of the time with a 32" bar. Plus, I'm shorter than most and when limbing I can use a 32" bar without it hurting my back as much as a taller guy. On steep ground the use of a long bar helps to reach your far side in the undercut. Because you usually fall your timber side hill on steep ground, your cut on the low side sometimes can't be reached. Also, when you buck a big cut off, you have to reach way over to get your bottom corner cut, or your cut will not drop off, or you will get hung-up in the cut. I very seldom use a 42" anymore, and if I do I run it on a 084. Mostly its just to heavy to pack around all day. The 066 with a 36" bar will do anything you want to do now a days usually. JJ know problem on the buttinski I like to hear what other people use. Dennis