Just read your Part I blog post, and I wanted to say that I went through the same basing issues with 10mm ACW. I use smaller 10mm figures, which can still be fit onto a 5mm frontage, and like you decided that 3 figures per 15mm frontage was as small as I could go, but still has proved very sturdy and flexible. I also use 1mm bases from Litko (would love to find a EU distributor!), but I also added 1mm magnetic tape on the bottom. This doesn't affect the look, and gives a little "grip", but most importantly allows the use of thin metal sabots when needed, or simply for ease of movement.
I'm wrestling with whether to start 6mm Napoleonics on 15 or 20mm bases - your collection gives me some food for thought!
Cheers.
Christopher