Is this enough power?

Good job getting the impedance data. sounds fine.
However, your job is not done yet! See if you can find some phase data. This IMO is the true test of 'good load/bad load'. Huge phase angles at low impedance will really drain all but the most robust amp. Speakers which are heavily capacitive do not like tubes....or perhaps the other way 'round.

Trying the various taps on the amp? Best idea yet.

Magfan - is there anywhere i can go to find out more about phase angles. that is something i am not familiar with. Does it have something to do with the slope of the impedance curve at a specific frequency?

That does help and the amp will work. I still caution you that more watts would help your system reach it's full potential.

This will be true on all classical recordings that happen to have low output levels. Your room is large with the kitchen figured in and 30 watts won't let you realize the full weight, scale and impact of your music.

I also found this and used google translate. Is the frequency response and/or axel deviation comment related to phase angles? Not sure if the wording is different because of the translation.

"Also by measurement the relationship between S-1EX and S3-EX is unmistakable. The frequency response looks almost like drawn with a ruler and extends down to about 40 Hertz. From five kHz is a slight ripple into play when the axial deviation of 30 degrees (dashed line), however, is negligible. Straightened out into the room, the Pioneer actually sounds a bit faster and more coherent dunk. The impedance is danzverlauf critical, and the jump response is in order, with the enormous time accuracy of their sister, it can not record the S-3 EX bass but because of the delay."

Thanks

Phase angle is how much current leads or lags voltage.
In a pure resistive circuit they are in sync.

The wiki has some good illustrations.
http://en.wikipedia.org/wiki/Power_factor

For stereo / hi fi, this presentation is most useful
http://www.hometheaterhifi.com/component/content/article/228.html

The main thing to remember is that any time current and voltage are not perfectly in sync, less power is delivered to the load.

It is pretty much purely electrical. Maggies for example, if you simply look at impedance may be considered a difficult load. This is not necessarily true, since the phase angle is moderate thruout the frequency range. Other low sensitivity speakers which like tubes may be like the Harbeth.

Here is a good example of a fairly large phase angle coupled with a low impedance dip. I don't know if these guys work well with tubes, or not.

http://www.stereophile.com/content/focal-chorus-826w-30th-anniversary-edition-loudspeaker-measurements