alright, first, you wont want to tape from 8th row center because you will have to run head height...everyone wants to say that DMB tapers are morons because we dont tape in the center...but the problem is that DMB runs a camera from the board and will not let your stand be above head height...and we are talking normal head height, like 5'9"....you will get too many screamers imho. This is why everyone trades over to the stack sides, because you can run higher, get the screamers out and also, it is a mono PA (one of the best sounding PAs on the road today imo). Now you can run as high as you want, anywhere behind the board, but quite honestly, I am not a fan of section taping (which is essentially what running behind the board is), but to each their own.
As for stereo configs, no, not most DMB tapers dont run AB...there are a few, but there are as many if not more, including myself who run a wide XY, or a DIN, because while the music may be mono, by running a stereo config you still get a pretty cool image by doing that.
Any questions, feel free to ask...there are a few of us here who have experience taping DMB and would be happy to give advice.