What your mics can handle is directly affected by your position in the venue. Two exact rigs in the same venue, music at 125 dbs, one rig directly FOS..the other in the back of the venue...which one is likely to clip first?
Ideally, you should go with whatever route will give the absolute maximum spl handling ability. Once you get into a FOS situation and find out that your mics just couldn't handle it (clipping) you don't get a second "at bat". If your already getting mics and a recorder in, a battery box is cake,..really. And on that thought, you might as well do it right and use a 3 wire BB (for the AT mics) then there won't be any guessing,estimating,maybes'..ect. I cannot even begin to comprehend going into a situation not being prepared to the best of your/my ability.