Help building first tube system.

At your budget I would steer you away from some of the "pedestrian" brands of tubed electronics like: Prima Luna, Schiit, Rogue and a few others that I cant recall. These are not bad products, just not nearly as good as others that cost a bit more. Within your budget you can easily afford separates which will always outperform an integrated. I would put as much money into the components and speakers as you can and then upgrade cables and other tweaks (be careful!) as your budget allows. Fundamental from day one are good acoustic treatments for your room. To suggest almost one third of your initial budget on cables and tweaks is absurd and bad advice IMO. I have limited experience with Atma-sphere preamps but the amps are among the best I have heard given the right speaker impedance. 

your 20K budget is more than sufficient to build something nice. Many of us choose amplification or speakers first and go from there. Good advice I've seen in this thread is "buy the best speakers you can afford." I have  a 20K system and half was spent on the loudspeakers.

Thanks to all who have replied.

The room has 10’ ceilings. Walls are drywall but ceiling is wood. Basement room, concrete slab with pad and carpet. 
Intrigued by the Raven line up of integrated tube amps. Anyone else have input on these? What about Cary?  
I guess I should ask the question, any recommendations on a reputable tube amp dealer in Chicago? Couple hour drive but probably the best starting point.

Thanks again and keep the advice coming!

To your question about Cary, I owned two Cary amplifiers, an AES/Cary AE-25 and a Cary Sli-80 F1. I was very happy with both but replaced the Sli-80 with my Raven Audio Blackhawk LE. Cary was started by Dennis Had and he was responsible for how highly regarded Cary gear has been. He still builds and sells amps under the Inspire brand but is no longer affiliated with Cary. Here's a discussion from a couple of years ago about the company and its products that may be helpful.
https://forum.audiogon.com/discussions/since-dennis-had-left-cary-has-the-company-built-any-new-tube-equipment

My budget was similar to yours, although I started with a smaller budget but then had to adjust upwards when I fell in love with a set of speakers.

For my $22k main rig, I put $10k in speakers/sub, $6k in integrated amp, $2k in source/dac/streamer (all in one), $1k in power conditioner, and $3k in everything else (power cables, speaker cables, interconnects, isolation, noise suppression, etc.).

FWIW, that’s what worked for me. Many might say I underspent on source to detriment of others but the only source I use is Tidal streaming (no vinyl, no cds, no digital storage) -- obviously if you care about those things then would have to skimp on some of the categories I went heavier on to fit them in.

Agree with what others have said on auditioning stuff. Try to make it happen. $20k too large a budget not to be quite confident you’ll like what you get. In-home always best but not realistic for many. I did all of my auditioning in dealer showrooms, probably 20+ speakers and 5-10 amps/electronics over a 6 month period. Research was well worth it, as none of the pieces I ended up purchasing would have even been on my short list when I started.

Sorry I don’t have tube recommendations for you, but I think listen to as many speakers as you can with tube amps and it’ll become clear to you. You’ll know when you hear it. Also suggest don’t foreclose on floorstanding speakers -- be sure to compare some of them against the bookshelves you’d otherwise get. My experience was that, even with standmounts and a sub, the sound of floorstanders was just so much fuller and with additional layers than the bookshelves could deliver.  I like bass so I got the sub anyway, haha. YMMV