"easiest"

In mild SD, I bet you will not notice any difference between a transplant in Sep or Dec. It's August, just do it.

I'm quite disappointed in my new AK that I put in the ground last Christmas day (btw, is that late enough for you? :) ) This summer's culms are coming up very inclined, then bow somewhat to the vertical, but still too inclined for my tastes, and give me bowed-in culms. I was expecting nearly vertical culms.

For your spreading question, I don't know if my AK initial behaviour will persist, but I planted the small AK division in the middle of a 24" tub, and now have the recent round of late summer culms shooting right at the edge of the tub. That's a pretty open, spreading clumper, imo, spreading a foot in 8 months. My year-old B. tuldoides is giving MUCH bigger culms and with much less spread from the original culm.

btw, I have a friend in Chula Vista thinking about putting in his first clumper. Do you know where he could see some B. lako or B. tuldoides or B. tuldoides clone X in SD?

Have your friend email this guy. sterlingwyman@netzero.net. He runs a small nursery in Ocean Beach. The actual nursery is in Vista with all of the species they propogate but he can usually get anything you want down to his place if you ask.