Got to play this yesterday - it went pretty well, all things considered!
We played to 8 banners and had a narrow French victory, 8-7, but were somewhat disappointed as the main armies hadn't really clashed by the time that happened, it having been mainly a cavalry and artillery engagement. So we decided to keep playing to 12 banners, and the French still eventually won 12 - 10 after taking the town.
It did take forever, though, even when we just played to 8 banners, and it felt like 90 percent of gameplay was like the first 20 percent of a regular Napoleonics game, where you're closing the gap, concentrating forces, and jostling for position. It took what seemed like Eons for the French to move their entire line up, and the British, having very little motivation to come off the hills, spent most of their time doing a lot of nothing.
I think Breakthrough rules as written may be better suited for Memoir, where all infantry behave like Light Infantry and so can move 2 spaces when ordered on the move. I may try a simple rule saying that non-light infantry ordered "on the move" may move 2 spaces, and hand-wave it by saying that they're still in column and haven't yet gotten close enough to deploy into line. It would certainly speed up games and add an interesting new dynamic.
