Hi grant, thank you.
The bases are as for Napoleon at War and the dimensions and guide are on the blog. Just go to the labels section in the right hand bar and find "basing guide". All the information you might want should be there.
I haven't played Napoleon at War for quite a while. I put together the Rolica scenario using the rules. The concept of the rules is very clever with some excellent design concepts. I wasn't a fan of the Flames of War direction they seemed to be heading towards and now the company have put the project on hold as they turn there attention to ACW! That said the basing system is very straight forward with units of 12 and 24 and I find it works perfectly with Carnage & Glory, which to my mind is a first class set of Napoleonic rules. I tend to flex the size of my units with infantry having four or six bases in a game to represent normal to under strength battalions without messing up the ground scale to any great extent.
Hope that helps, cheers
JJ