Hi guys, been running a single 2000ma Li-Poly with a duralite 6v regulator and one HD JR Switch for nearly 9 months (about 50 flights) and no problems at all, I personally think the redundancy thing on this size model is purely ones own choice and not totally necessary ( my opinion only ;-) I run a Brison 3.2 on a Extra special, digitals all round and have managed a very light setup (15.5 pnd)
oh and I run a single 4.8v 1000 ma ni-cad on ignition, this is Brisons reccomendation: any good quality 4.8v 800ma or above pack is fine for ignition, can't imagine it would be too much different for the CDI units..... good luck with yours