How much power do I need? Find out using this method...

Thanx cal3713. Great link! Every audiophile should have a meter if just to test fuses and continuity in other devices and as you found out relatively 
decent ones can be had for little cash. Another nice tool to have is a dB meter to check volume levels. This one cost a whopping $15.00
https://www.amazon.com/Decibel-30-130dBA-Backlight-Flashlight-Included/dp/B07G8F8TK2/ref=as_li_ss_tl?SubscriptionId=AKIAJO7E5OLQ67NVPFZA&ascsubtag=3711
If you want to test the effectiveness of your tube traps just put on a 30 Hz test tone and walk around your room with the meter. If your variation is less than 3 dB away from the walls you are doing a great job.

roberjerman, your ears are shutting down because of distortion not volume. I routinely subject innocents to 95 dB after appropriate warm up.
They start trying to talk to you not realizing how loud it is. Now most rock concerts are up at 110 dB but that volume is unnecessary to get the feeling you are there without damaging your ears. 95 dB is perfect. But, very few systems can do that effortlessly.
gs5556, I can easily hear one dB. 3 dB is painfully obvious and 6 dB is an earthquake. You need to live with a system that accurately measures volume in dB or a dB meter. Volume at distance is more complicated because you are listening to a stereo pair. As you move closer to one speaker you move away from the other. Volume one meter out from one speaker is almost the same at the listening position. Just use the meter at the listening position. That is where it counts. Measuring power of the speaker terminals with a high impedance meter is perfectly appropriate. It won't be a perfect number but close enough to give you an idea what is happening.   

Hi elevick. You have solved the problem by having very efficient loudspeakers and with your Mac you should have no problem making your ears bleed as long as the speakers can perform at those volume levels. Many if not most can't. But I have no experience with your speakers. The problem for most people running those levels is that either the amp is clipping transients or the speaker is distorting. 
I was responding to gs5556's comment about differences in perceived volume levels. To any listener a 1 dB increase in sound pressure is obvious, 3 dB is a rather large increase and 6 dB is a huge increase. If I were to increase the volume 6 dB on one speaker only the other one would literally disappear. Try it. There is another issue with point source speakers. They way the cast an image makes them sound surreal at loud volumes. It is like having the volume of the 6th row back in the 20th row.
Line source or linear arrays solve this problem by casting a much larger image so the volume and the row match up. 
In no way do I listen to all music at 95 dB. Also remember that the rating of your speaker is at 1 meter. I listen at the volume the music at hand sound right. There is a rare record that I will listen to at 100 dB like the Dead's Infra Red Roses. What fun to blow peoples brains with that one. If you want to know how your system and house deal with very low frequency transients get that disc. It is a selection of drum solos. Every recording has a "right" volume level depending on the type of music and the way it was mastered. I miss spoke. Some recordings have no right volume level usually because they are mastered poorly. As an example I was listening to Paul Simon's Graceland last night. The instruments are way out in front of his voice like he is standing in the next room over. So either the band is too loud or his voice is too far away. I love the music but it could have been mastered better or at least more realistically. Most people think this is a great recording. Waiting For Columbus is an excellent job all around. Turn it up and the band is right there everything in perspective. It was probably mastered off the sound board. For studio recordings check out The Smiths, The Queen is Dead. Great job! Waltz for Debbie I listen to at 90 dB. These are peaks by the way, peak volume measured with a dB meter. My preamp measures volume in dB but that has nothing to do with absolute sound pressure levels. dB is a relative term.

Quite a few live recordings have overdubs as all kinds of stuff happens. A pickup fails or a mic started distorting etc. A good mastering engineer can put an overdub in perspective. Frank Zappa was famous for this. Let me know what you think of Graceland. I listen on a line source system and the perspective might be different on a point source which is what most studios use for monitoring. I don't think so as it is usually just a change in sound stage not the relative position of the instruments.
The way Graceland was mastered originally (has it been remastered?) it sounds as if the engineer wanted to make sure you could hear every detail of every instrument so he moved them all up front. The detail is attractive but a bit surreal. If he had moved Paul's voice up front he would have been way to loud.