I also have a set of the SAM’s and they are a special speaker you may want to look at adding a subwoofer with SAM’s or preferably two of them.
I run SET 300b tubes and have been also looking at many speakers suitable for low power. I have a very nice and wonderful sounding set of Living Voice speakers 94db. These are some of the most musical speakers I have ever owned.
I’ve also owned AudioNote AN/E’s another great speaker but they do need a room with two corners to sound their best. they are not quite as efficient as the spec’s claim though.
Voxativ’s are a more refined (and much more expensive) version of what you have with the SAM’s but I have only heard an older first gen version but they are nice as well.
I did a write up of the SAM’s here a week ago and covered much with the AN/e’s and LV’s when I compared them to the SAM’s.
coincident speaker, spatial audio, Prue audio project, Zu audio, tekton and supravox field coils are a few others that come to mind that make high efficiency speakers.
Charles1dad is another member who has had much experience with low power amps and high efficient speakers he may chime in and give you some more suggestions.
I’ll be honest the SAM’s do some things that only full range drives can do and you may miss that with something else, I know i’m seriously thinking of selling my Living Voice speakers and buying a couple subs or possibly the HO floor standing version.
just to add its not necessary to leave tube amps on all the time. and frankly class A amps don't need it either 5 mins and your fully heated up.
In this day and age there is not reason to waist the energy turn them on grab a drink, kiss the spouse and go listen.