Thanks for the thoughtful responses... very helpful!
Lots of good advice already given. As mentioned, try to slow the sheep so that they arrive at a walk, or slow trot. I like Pearse's way of having the dog fetch the sheep to him on the side they will eventually wrap around, and handler moving toward the post at the appropriate moment. In the event that fails because of the draws near the post, or other reasons, it has worked for me to have my dog flank-off the appropriate direction to move the stock to the correct side of the post as they are slowing toward it, and then as the sheep seem to be committed to passing on the correct side, I flank my dog wide to the opposite side, to say about 10 or 2 O'clock. The key sometimes, always depending on your dog and the sheep, is to bring your dog around the post in little increments (little pieces of the pie), rather than one big sweeping motion. Perhaps 2-3 or more stops as the dog flanks around the sheep and the post. Incremental flanks have the effect of preventing the sheep from heading toward nearby draws, so often found on Nov-Nov courses. Additionally, I have found, for me, that this maneuver keeps the sheep near the post/handler for more trial points. And yes, it maintains the flow to prevent the sheep from stalling/stopping at the post.
At some trials the moment the sheep are about to turn around the post to go back down-field, they are looking directly at the exhaust pen, so in this event, the final flank may have to be close to an over-flank, in order to prevent them from building-up speed toward the exhaust draw. On the other hand, if they do not need to be slowed due to a draw, try not to over-flank your dog as they begin to direct their heads down-field to the out-drive panels. An over-flank at this point could have the effect of pausing the flow, and you may have to flank your dog back to get them moving again.
Best wishes. There are lots of variables, so watch others, read your sheep and "suss-out" (study) the course. -- Kind Regards, TEC