30 to 50 watts seems to be all I desire

Addendum

The PrimaLuna I referenced has 72wpc with current output tubes, so in a different class than the Decware. But input sensitivity of amp is still relevant. 

That Decware amp had gorgeous sound though! Just wish that input sensitivity was adjustable, 20 watts might have been plenty.

I own the Magnepan.7’s and l have two amps A VAC PA 100 100 tube amp and a Spectron musical MK lll SS amp As you know Maggie’s love watts/current My VAC sounds magical with the Maggie’s at 100 watts per side But when l use my Spectron with 500watts@8ohm 650@4ohms and 1,200 watts@1ohm and the capability of producing 60 amps for 500 milliseconds, it really makes the Maggie’s come alive with dynamics, inner detail and sound stage

Watch "magnepan 7's doing their thing" on YouTube
https://youtu.be/bofnCCYuR48

14 wpc [tube] for my Bozaks, 100 wpc [tube] for my JBL’s, 850 wpc [ss] for my Maggie’s. Different tools for different applications. I listen to many genre - mostly old school: jazz, rock, country, blues, R&B, bluegrass - all of it! [and like you, not terribly loud - medium volumes]

I agree with the OP…30-50 watts is adequate. I’m running a Pass XA-25 and it has driven everything I’ve wanted beautifully. 300B’s are probably in my future, so less power still. 

there is a difference between a speaker being sufficiently driven versus the same speaker being driven to show all it can do at higher volumes

alot depends on the type of music, how much dynamic range is needed

smaller wattage amps often do the mids and nuances very well, but will sound compressed and/or flabby/unconvincing in the bass when the music become more dynamic

big power amps might not be as highly tactile at lower volumes but will provide a great sense of ease and naturalness as the music becomes more dynamic and complex

the sweet spot in all this depends on the specific case... speakers, taste of listener, type of music listened to, room, and volume levels