I typically listen in the low 70db range. High 70’s sometimes. Most of the folks I know will only occasionally listen in the 80’s. But I think the better the sound quality the lower the volume… that has been my experience.
Virtually all speakers have a sweetspot… it can be only about the size of your head with planar speakers and open up considerably to be a couple feet with some dynamic. Omnidirectional will have the largest.
If you haven’t spent days getting your speakers perfectly positioned then your probably not getting remotely what they are capable of. Start with equilateral triangles… I would search on speaker positioning. Toe-in is critical. Your speakers are capable of amazing sound… imaging.. soundstaging. Lots of work required to get the most out of them.
More power will solidify the bass make the sound more effortless. In general tubes can be more musical, but implementation is everything. Your speakers will probably sound better with more power. On the Other hand my
In general, you want your meters to stay on the left three quarters of the scale.
Most systems have a point where they “sound best”. I think my observation is that the better the system is, the wider the range of sounds good is. My system now sounds good at almost any volume, I have the best system that I have ever owned. Actually my dealer says it is the best system he has ever heard, and he has been in the business for over twenty years (photos under my user ID).