The shiny bowl is as light as any bowl, imo...and produces a response equal or better than any other bowl Ovation came out with, acoustically, imo.  As many times as this has been kicked around, I think it is clear that it is a sum of the parts, instead of a single part.   

I just finished reading an interesting article that discusses using computer modeling to isolate the manner of sound generation in classical acoustic guitars. Among other things, it mainly talks about the relationship between the top, the air inside the guitar and the back/sides.

See: Mathematical Modelling and Acoustical Analysis of Classical Guitars and Their Soundboards

As expected, there is a direct relationship between the movement of the top and the back due to the coupling of the two via the air piston contained inside the body. And, as expected, the top moves a lot more than the back because the air is somewhat compressible and the top is made to be more flexible than the back.

WRT your observations, it's possible that the earlier thin cloth bowls created a response that is slightly out of phase with the top and cancels the propogation of sound waves throughout the body and out the sound hole. The stiffer bowl of later guitars vibrate less. Because their movement is more limited due to their thicker material, the sound waves are not canceled.

Imagine, sitting in a bathtub full of water. If you slide forward and backward and wave can be generated which sweeps back and forth through the length of the tub. The amplitude of the wave can be increased by moving in time with the wave, but the timing (frequency) of how long it takes for the wave to reach from one end of the tub to the other is controlled mainly by the length of the tub. A longer tub would produce a lower frequency and a shorter one a higher frequency. Now, if you move out of phase with the wave, you can cause it to stop altogether.

This is similar in concept to the thinner back which is more flexible and bounces back more quickly, which could accelerate the sound wave so it leaves the back at a higher rate than it arrived. So, instead of the top and back moving up and down together, they are now acting more like a bellows where one is moving up while the other is moving down.

Also, as expected, thinner, more flexible material favors lower frequency sound waves (bass) and thicker, stiffer material favors higher frequencies. (treble) This becomes even more complicated when you have hand-laid, woven cloth fiberglass bowls whose thickness (and vibratory response) is controlled by how much resin the lay-up applied to that bowl. So, you could have one bowl that has more or less bass and more or less treble, depending on how it was laid-up. One thing that the SMC bowls did introduce was consistency of thickness and hence, response.

As Jay points out, the end result is a sum of the parts. It's difficult to compare one guitar to another mainly because of the wood involved. Even when two guitars are built identically, the wood used in its construction has a lot to do with how it will sound.

One of the things I found interesting about the documentation of the prototype Adamas guitars on the Ovation Tribute site is that by using composite tops, the factory reduced the number of variables required to produce consistently good-sounding guitars when compared to all-wood guitars.

But even so, the factory still struggled to produce guitars with a consistent frequency response that their ears said sounded good. One would sound really good and the next, not-so-good. They had reduced the number of wood components to just the birch core of the top and the braces, but still have inconsitent results which needed fine-tuning.

The above paper also talks about the relationship of the neck to the body and that even it can affect the final sound of the guitar.

From the plot, it looks like a well-balanced sounding guitar.

For a comparison, here's the plot from what they considered their optimum (prototype 26-3):