Confused for the best connection between my Elac speakers to power Amp

It is strange when I was a kid. 16 ohm speakers were real common, 24 ohm.. I still use the highest ohm out just for the tube breakup. Tube amps don't normally double in wattage they stay the same. 2 ohms to 24 ohms that Mac will put out about 75-80 WPC. I let my ears tell me the story. High E speakers, above 90% they can get noisy, that TAP can make a difference. Just listen..

Regards

No worries impedance is approximate. 4 or 8 will be fine. The only real worry is that you have something crazy like 1 ohm speakers and the amp can't manage that low of an impedance. You are fine. 

Thanks. will give it a try. Are you sure it doesn't overload (sink high current) from output stage of PowerAmp? 

Use the 8 ohm taps, you will get the best out of the amp.   My speakers are rated at 6 ohms and the 8 ohm taps on my MC302 ampsound the best.  In my office system, my JBL speakers are rated at 4 ohms and also sound best on the 8 ohm taps on my MA6600 integrated. 

Use the 4 ohm tap. Impedances will fluctuate. 

Tried both no difference. I do not want to harm the output stage of amp or input stage of spkrs

Try both. If you can hear any improvement just leave it on the tap that sounds better. I doubt you will hear any difference!