[PvK]

Well, my theory is that it's fine to put them in the back corner, or back middle, and that Hold and Attack is best, or Guard Commander with the commander on Hold Hold ... Hold Attack Rear, and that it's best to have as many such units as possible, and it's best to have as many Groups of such units as possible.

In watching these things, it seems to me that if one of your own Groups has targetted an enemy group, it seems more likely that an Attack Rear group will bypass those and go for an unengaged group. So the more Groups on attack rear, the more likely to get to the actual rear. But the numbers in each group seem to help too. If you have a ton of units on attack rear, then some tend to get to the actual rear, especially if they are flying.

PvK