trust your ears!...
Hola Mattables. I think that it depends on your liking. Sometimes the 8 ohm tab is more musical than the 4 ohm, and viceversa. Of course, I'm not saying that you should use 8 ohm tab. What I'm saying is play different kind of music thorugh your Clarities and listen the scenario. Play heavy bass music and also strings, wind instruments, vocals and percussion. Listen carefuly and choose the one that you like most. The setting will not harm your speakers or your amp. With tubes, you can match your liking. In a general way, 8 ohm tab will give you more bass than 4 ohm. Try to listen again the scenario, the size of the instruments and not having ping-pong forward-to-back percussion instruments. (too much highs will produce this problem). To my liking, I will do several tests before make a decision. I have the Prodigies now, and I'm using the 4 ohm tabs at my sonic frontiers power 2 amp. When I listen my CLS IIz, I use the 8 ohm tabs...as I said before, it is my liking to set up my speakers in my room this way...and I like a lot the sound that I get from any of them. Trust your ears and have fun!
Regards from Costa Rica,