Power Handling Question.

Line arrays with 7x Parts Express #269-912. Linkie:

http://www.partsexpress.com/pe/pshowdetl.cfm?&DID=7&Partnumber=269-912

They're wired kinda funny. Since it's 7 drivers, I couldn't get a nominal 8-ohm load. I wired the 3 in the middle in series and the 4 on the outside in series, and then the two runs in parallel (make sense?) and my multimeter reads 6.2 ohms DCR. (I don't have equipment for measuring impedance vs. frequency... yet.)

My question is this: the power handling claimed for these drivers is 10 watts RMS; 20 watts peak. (whatever "RMS" and "peak" mean these days.) They're also intended for full-range use, which I don't use them for. They're crossed over at 200hz, 12dB/octave. 12dB/octave is the right slope to keep excursion constant below the crossover frequency. This should help my power handling, right?

What I'm wondering is, can I somehow find out what the real power handling of my towers is without smoking one to be sure?
 
The drivers connected in the 3 line will be putting out more sound than the others, so the limitation will be whatever those manage, as a starter for 10. Would that actually not even be a proper line array as the SPL from each driver will not be equal so a possible distortion/curving of the polar response occurs?

You could speculate that the filter offers sufficient protection to mean that the limiting factor is the voice coil thermal capability. Therefore simply draw out the network as resistors of the rated wattage and work backwards to find out the input power.