Speaker impedance selection for McIntosh MC-300 ??

I have a a pair of Paradigm Studio Reference/100 v.2 hooked up to a McIntosh MC-300. The Paradigms specifications indicate that these are 8 ohm speakers. However, a review of the Paradigms in the June 2000 issue of Stereophile states "....the impedance, however, drops below 4 ohms between 55Hz and 210Hz, with a minimum value of 3 ohms at 90Hz (fig.1). A good 4 ohm-rated amplifier should be used with the speaker." My question is: The Mcintosh provides different amp output taps for 2-4 ohm speakers, 4-8 ohm speakers and speakers 8 ohms and higher. Currently I have the Paradigms hooked up to the 4-8 ohm taps. Is this the best way to hook up these speakers or should I hook them up to the 8 ohms-and-higher tap. Any advise would be appreciated.