Seldon,
This came up in our last game, hence I mentioned it.
The precise example, I had artillery positioned with a unit of light cavalry (abrest) directly behind it, with the intention of using them to charge through the guns to deliver the coup-de-grace charge when the guns had done their work, and to protect against any skirmishing or other attacks which would otherwise prevent my gunners from doing their work.
I had infantry deployed beside the guns, all in all a nice defensive position.
My opponent came on in the usual way, although aimed slightly more toward my infantry.
when the time came to charge, it was infantry first to his infantry front - pinning him in column, and my cav coming in on his 'edge' (comng from a frontal position, there was no quesiton of a clean flank charge)- when we remembered the 'covering half unit ' rule, and so my cav didn't meet the criteria, and lost half dice I was expecting for this particularly skillful manoever.
had they been in wave, they would have covered more than half, and I would not have had the penalty.
Looking over the situation, it immediately became clear that unless he had brought cavalry into the general area of my guns, I was never going to benefit from the cavalry being abrest and was always at risk of not getting a clean frontal charge, and thus, missing half of my target - and hence, I should have started and remained in wave formation both to enable swifter and sharper turns, and to ensure that any charge maxmiised the probability of covering all of the target unit.
We then applied this game reality to the actual tactics, and they fit - cav would arrive in close waves on infantry, hoping that a discharge volley would allow the folowing squadron to charge home against emplty muskets.
Luckily, I had by this stage already thrashed the enemy by skillfully offering up my undefended objective to distract him, so we filed the information for future reference.