In my experience, 2wpc has been surprisingly powerful with my Omega CAMs. I'm not using Decware gear, but rather a slightly lesser powered Yamamoto A-08s 45 SET amp. As I assembled this setup recently, I could only go off other user reports and my own calculations... so I was very happy to hear that my math had worked out on what dB I had hoped to be possible. The resulting sound is the best I've ever heard, replacing my previous (also excellent) Eminent LFT-8b planars driven by 130wpc Mosfets.
A few caveats -- First, I'm running a carefully matched 15" Rythmik subwoofer to fill in the bottom end... which I *very highly* recommend (or a similar 'fast' sub). Second, I'm listening near-field, being only about 7 feet from each driver in an equilateral triangle configuration. Third, I only prefer to listen at moderate SPLs anyways... somewhere in the ballpark of 80dB. I knew I would want to have at least 15dB of headroom for transients and peaks, so since the CAMs are rated for 95dB at 1 watt, I figured I should be good...
Not only am I good, but I'm totally smitten

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My room is an irregular shape, but it's roughly 280 sq.ft. with cathedral ceilings. The speakers are about 5 feet from the front wall, and a little more from the side walls. I sit about a foot behind the middle of the room, with my rear wall about 9 feet behind me, and the side walls about 5 feet away... So, essentially, I'm doing a near-field setup in the middle of a bigger room. This sounded superior to me versus using the surrounding space to gain more distance from the speakers. That extra surrounding room is not wasted, but rather allowing for minimal reflections on all sides. After many, many placement variations with careful comparisons using the same test tracks, this was what prevailed.
I bring up positioning because, of course, that is going to have a huge impact on whether you will feel that you have adequate SPLs or not when using a flea watt amp... Nearfield is your friend in multiple ways.
Have fun experimenting!