As much as I love sorting, penning is still huge here in southern Alberta and we don't have much sorting available to go to. One arena has been doing three man sorting weekly over the winter but it runs at the same time as a penning practice that is run by a 5 rated rider who coaches us during our runs. So we have been doing the penning instead.
The smallest I have sorted in is 60' pen and the average time was in the 40-50 second range on ten head. Some of the top riders were faster of course though.
Sorting is a great way to slowly introduce a horse to the type of cattle work required in penning. When I bought my mare she was all go so I only sorted on her for a year and then slowly introduced her back to the penning.