I'm around the bend for grasses too. My knowledge is limited though.

I divided Karl Foerster and Miscanthus "Kirk Alexander" this Spring. Karl is very easy. Miscanthus are more difficult. But yeah, I just dig up the rootball and use the straight spade. With Miscanthus I couldn't get through the top, I had to get at it from the side. I never tried to wash the soil from the roots...just replanted.

Karl divisions all took. Miscanthus had some failures.

I'm also one of those guys that buys grasses at nurseries in the Winter when they're discounted 40 percent because they're all cut down and scraggly looking...then I divide them. Cheap way to get lots.

I've wintered both ways, either in a pot sunk in the soil or planted in a holding bed. Planted in pots sunk in the soil are much, much easier to move in spring.

Donn,
Why do you want to make divisions of your warm season grasses in the fall?? I have not heard of great results from dividing at this time of the year.

As for division techniques, the grass nursery that I worked for NEVER cut divisions apart no matter how big the clump. Division required strong hands and arms. We would shake the dirt off the root ball (as much as possible) and then pry the grass apart. The prying part got easier as the clumps got smaller. The MAIN reason for using this method was to get every possible division from the clump.
Personally, I advocate cutting the clumps into manageable sized chunks and then pulling them apart. Much faster and much easier on your body.
1 - 2 year old plants should still be fairly easy to pull apart without cutting.
Sorry I can't comment on the bare-root part ~ I have never needed to do this.

I have some folks who want to trade divisions in the fall. Otherwise, I'd wait until spring. Maybe I should just put them off until spring, and not take any chances.