More Book of War. This time my 'favourite' topic: basing. Controversially (since no one else seems to think this is a good idea), I have gone with nominally single based troops. That's nominally, since you can often get away with multi-based troops, just like you can in other games. I have a whole Gondor army for War of the Ring that is multi-based and I used dice to mark casualties. You can do the same sort of thing in Book of War but you will want a little more flexibility in your multi-basing. Some sort of combination of 6x4s, 4x4s, 2x1s, and singles will work well. You will need to vary unit frontage and depth. Also, certain units have the option of forming up in wedges to try and break enemy formations. The minim frontage for infantry and cavalry units (wedges aside) is 100mm and each rank needs to be filled completely before another can be started. Part of combat resolution is based on the number of ranks, and to count, ranks have to have as many figs as the first rank. Any troops that don't contribute to a fight (because they are too far back) can be freely placed anywhere, so the odd bases out can sit at the back to act as casualties.
In order to keep some compatibility with other games like the Warlord stable, Impetvs, WOTR, and Warhammer - There are four main base sizes for units of multiple figures: 40mm square for larger things (Ogres!), 25x50mm for Cavalry, 25x25mm for Light Infantry, and 20x20mm for close order Infantry. Skirmishers can be on either 25mm or 20mm squares. If you have figs on 25mm rounds for WOTR, they can be sabot based as Light order foot or used as skirmishers.
In a wedge, Cavalry get to count as up to 6 ranks. The model at the point of the wedge is not counted when determining ranks. All of the models at the edges get to fight. So for example, a unit of ten cavalry give up three models worth of attacks in order to count more ranks when it comes time for combat resolution. Hopefully it is worth it as you have to inflict more casualties in order to break the enemy. Larger units of Cavalry lose a lot by going into wedge formation but this may still be worth it vs enemies that are numerous but not very tough.
Constructive comments on the system are welcome. For earlier Book of War notes see "Command and Control". Thanks for reading.