First Watt SIT-3 proper speaker matches


I have a SIT-3. I understand that it mates best with 4 ohm loads. I’m trying to find out if the amplifier is compatible with some 8 ohm loads. I am considering the Focal Kanta speakers that are 8 ohms and dip down to 4. The Focal Sopra 1 have been reviewed well with a 12w Valvet singled end solid state. I know there are other factors aside from impedance and efficiency but I’m not clear on the topic.
5560
I have a SIT3 and Tekton Design Ulfberhts which are rated at 99dba at 4 ohms. The SIT 3 will drive them for most music but not all . Tekton just came out with a speaker made for SET amps. A friend of my heard it and was quite impressed. I think this speaker would be a great match for your new amp that you are very fortunate to have as with the right speakers it can be magical.
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I'd think any of the SET tube guys speakers would be up your ally. I've tried and liked the above mentioned Omega SAM's, I own and love the Living Voice Avatar 2's (look further up the chain if your budget allows wonderfully musical speakers, also note UK pound makes these a much better buy right now), Tekton, Zu audio and Horns are a few others from the top of my head. Try searching high efficiency speakers here, there are quite a few good threads. 
I run a SET 8wpc amp so I'm familiar with your issue and its not backwards you just need to focus on higher efficiency speakers above 94db, depending on your listening volumes maybe 98db if you like it really loud.