Pulled the trigger on a Moon 861! Hope it pairs well on my Focals

I just got it hooked up to my McIntosh C12000 preamp and the Eversolo z8 streamer/dac. I have to say, compare to my Luxman 595 class A amp it sounds thin. My luxman 595, although on the bright side, sounded way fuller and even more holographic.

Compared to the what I heard in the audio store (McIntosh C12000 preamp,  DynAudio Contour Legacy towers and the DAC from Moon streamer(not sure if it was the 891 or 791) there is hardly any bass at all.

The Moon instructions say that ’The performance of this device will continue to improve during the first 100 hours of listening.’... is that why? Will it be that significant? 

Typically the sound will change a lot... being less trebly and more natural... often takes a lot more than 100 hours. 

I'm not sure why, but many companies are shy about documenting the  long burn in... even through it is required. My Audio Research gear took 600 hours to stabilize and even after that there was very slight improvements over the next 400. I burned in three of the same amps... and it followed exactly the same pattern.

I’d run it 24 x 7 for a couple weeks. 

So far I have about 10 hours on it. I am starting to hear the beauty come out of it which is really nice. 

One thing that bothers me, though, is.... currently I have just the Eversolo Z8 DAC on it. I have the McIntosh disconnected while I burn 100 hours (in about 2 weeks). 

I have the Eversolo at 70% volume and I feel like it's not as loud as I would like it to be. I can go to 80% but it gets a bit to boomy and tiny bit muddy. For instance, my Luxman 595 is super loud at 60% volume, I can't go louder without blowing the speakers. Will the Moon amp also get louder as the hours burn in? 

So, you are using your DAC straight into the amp... that is the issue. It is the input to your amp that determines the volume you get out. Your preamp should provide the input voltage (I think that is the parameter). An amp does not vary its amplification... that is what the preamp does... unless your are using your DAC as a preamp as w'll (unlikely to sound great). Should sound great with lots of volume when you put your Mac back in. 

@dman777 matter of sensitivity and gain matching. Don’t worry about it for now. Break it in first. 

Changing an amplifier is a major impact on the system. It’s got to be matched with speakers as well as with upstream components and room. Don’t exclude the possibility that you will need to readjust speaker placement. But don’t do anything at all until you have a minimum of 200hrs on it or you will be chasing ghosts. 
Good luck!