4 ohms , 6 ohms, or 8 ohms???

How do you determine that the Cantons dip below 4 ohms is the low range? 

Never mind. Just reviewed link. I appreciate that feedback. !

While Erik's point regarding being very careful in buying any tube amp for this speaker pair is certainly good advice and true, it should be noted that there are also tube amps that could likely annihilate and disintegrate them as well. Like this one http://www.atma-sphere.com/Products/#MA-3

That said, I'm in the SS camp.

In answer to your question about whether or not it would be preferable to hook up to an amp via 4, 6 or 8 ohm, my opinion would be to go with "8" to essentially lower (with respect to 6 or 4) the current output of the amp and in so doing make its life a little easier per se and lower your electric bill. However, I'm not certain if there is an audible advantage in using a lower ohmic value connection so I'll await the input of other more knowledgeable folks than I on this forum. I don't think there is an audible difference.

No worries, unless you live and breathe this stuff those graphs don't make a lot of sense. :-)

And while the graph does have an impedance below 4 ohms for most of the bass up until around 700 Hz, the operative word is "most". There is also a small range (say 70-90 HZ) where the impedance is up above 10 ohms. So the question raised as to which ohmic value to hookup to on an amp is certainly worthwhile trying to understand.