That sounds like an overly expensive option. I have seen plenty of the 2008 and 2009 Chargers (don't think the 2010 Chargers changed really) with one vertex per reverse light and they seemed to get the job done just fine. Couple the LED Inserts with the TLF and that should be plenty. I would add more warning to the rear deck or some LP LEDs before adding that many vertexes to the rear of the vehicle. I think the cost would out way the performance when considering using other lightheads.
In terms of cost, the Vertexes to the rear are going to cost about $536 for 8 of them. You could use only 4 ($268) and still have another $268 to spend on a nice deck light or a combination of LP LEDs and some deck LEDs (LED3s and some Ghosts or XP63s for example). You could even do the Charger TLF and a pair of vertexes, and still have enough money left for an LED TA and/or warning light for the rear of the vehicle. I think those options would be much better in terms of warning power and effectiveness compared to the all vertex solution.
If you decide to go ahead with using 8 vertexes to the rear, flash the two in each light together, otherwise I think you really defeat the purpose of having two per light.
All just my opinion though. Hope that helps some.