Warrenh, FWIW, ZU has made a 30 ohm version of the Definition (and your set can be easily modified). It works great with our S-30 and the power is nearly unlimited as the S-30 will make nearly 50 watts into that impedance. ZU knows this- they built the 30 ohm Definition for the S-30 as they had one on hand for years. This amount of power will get you on target.
I know a lot of people think its crazy to run power levels like that on a speaker of that efficiency, but IME you have to if you want to reach life-like levels that real live music often plays at. A typical orchestra can easily hit peaks of 115-120 db. You can't do that without power and without efficient speakers. The key is make sure the system does not produce excess loudness cues, else it will be too harsh to run at volumes like that!
The loudness cues I am referring to are odd-ordered harmonics, and at vanishingly low levels, but our ears can detect very slight amounts (100ths of a percent) with ease since the presence of odd orders is how the ear detects volume. Most transistors will generate too much odd-ordered content to be usable on a speaker this efficient- you really do have to use tubes, preferably triodes for linearity since you can't run any feedback either. This is BTW exactly the sort of thing we built the S-30 for :)
