Im an self confessed basing obsessive and have been musing over my napoleonics for some time. I decided that putting them in 3's, while flexible, is too fiddly and i prefer a more irregular look...
I tried two methods. One was to use the DBA standard 40x20, the other to use 30x20. While I always base shoulder to shoulder I decided to make the second rank thinned out. This allows more frontage, per figure and gives a more irregular look.
Prussians based 24 figs, 6 per 30x20 base
This pic shows how the line looks very think compared to the NB standard.
With 26 figs (4 bases) you get an ok square
and an ok column
With 36 figures you can a really nice column and square which really suits my ragged 1813 prussians and early french I think..
This is 40mm x 20mm which is less flexible when I want to use 24 man battalions. This is because with 3 bases you cant make a decent square as above. It is however perfect for my ottomans who cant form square anyway :)