fwiw, I used 13Gauge strings when I took at 25.5 scale length instrument down to B standard (with drop A bottom note). This was nearly right. About the same neck tension as 10s in standard tuning (I pre-calculated it, and it wasn't far off when I came to adjust the floyd rose).
Given a proper scale length (muahahaha), there's no reason that you can't use drop A tuning without perfectly responsive strings and a brutal, sharp attack. Hey, it also works well for blues!!!
Roo