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.
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.