I would prefer option 2. In example, you want ~22 CV per hex in your five hex section of front. That's goal 1, met either way. Goal 2 is freeing up units for operations (elites and some/all of the workhorse divisions).
Advantages of option 2...
- less total CV, but two extra divisions (25 vs. 23) free for operations.
- less units to stack
- less CP used in HHQ
- no lost MP if the front is mobile from gathering and recombining broken down workhorse regiments. Or lost MP advancing regiments into enemy control.
- less total CV, but more resiliency in the defenders. If retreated and attacked again, they probably will retreat, not rout because they were unready after only one attack. This is probably the biggest advantage I see at first glance. option 1 is an eggshell defense, the dregs will crack and rout sooner.
More full divisions available is more important during offensive actions - they use less MP moving forward for example.
The differences are not huge. Option 1 might be best on a static front in a defensive stance. For offensive stance or fluid fronts, ideally I'd try to build option 2. The five workhorse divisions are less capable, yes...but add one to the twenty operational elite and three operational workhorse divisions, set the other as reserve for just in case, and I think I'd be ahead of option 1.
question: how about digging in? I'd think a division at 67% would build up fort levels quicker than a division at 33% and a regiment at 100%. I don't know the math involved, though.
This is a good, thought-provoking exercise. Thanks, Telemecus :)