Noob Planar Speaker Advice Needed

I think your room is just fine.
However, true "panel" (dipole) speakers can be of three basic kinds:
Electrostatic (MartinLogan, ET, Acoustat, Soundlab)
Electrodynamic (Magneplanar)
Full-range ribbon (Apogee)

They're all technically planar dipoles (flat, and radiating both front and back) but that's where any similarities end -- both in terms of sonics as well as the equipment necessary to drive each kind optimally. So you need to do some auditioning and reading so you get clear on their differences. You will definitely discover you prefer one type (and maybe one brand) over the others; but this is not the time to solicit recommendations, since you haven't yet discovered which of the three types suit you best.

I can tell you this: If you like the sound of Maggies, you probably won't like the sound of (any) electrostats as much, and vice versa. And if you like the sound of a full-range planar ribbon like the Apogee, you won't like either stats OR planar magnetics ;--) If you can't decide, you haven't listened enough ;--)

In the meantime you can click on my 'System' link to see how my CLS-IIz system has evolved over the last 20 years ;--)
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I have some thoughts.

Maggies vs. Stats:

1.) Maggies are not satisfying at low levels, so like me, if you use your system for long periods at background levels (in between actual listening sessions) you probably won't be happy. Electrostats remain full-bodied at low levels.

2.) Maggies can't (practically speaking) be driven with tubes. They require a lot of voltage in each watt of amplifier output, a feature of SS amplifiers. The opposite is true of electrostats. They require current more than voltage, and tube amps deliver more current (per watt) than SS amps.

3.) If you're willing to bi-amp, you can improve the performance of the larger Maggies by putting a tube amp on the ribbon tweeter/midrange, and a ss amp on the bass panels. However, with the (current models of) MartinLogan electrostats, biamping is not necessary since they already have internal ss amps for the woofers, allowing you to use a nice tube amp for the panel -- in oher words, they are sort of "pre-biamped" ;--)

4.) The smaller Maggies are like smaller box (non planar) electrodyamic speakers. Less is just less. Small electrostatic panels sound just like big ones -- as long as the room is also small; and as with all stats, will need some bass supplementation.

5.) All the Maggies except the very small ones, will do best with solid state amplification. If you opt for a MartinLogan hybrid (stat panel + built-in woofer) then for the best result for the dollar, buy one of the recent models with self-powered woofers so you only need a decent tube amp (the external amp) to drive the panels; giving you the best of both worlds without the expense and hassle of using two different kinds of external amps. With an SL-3 for instance, you won't get the best out of the panel with just an SS amp, nor will you get the best bass if you try and get away with just a tube amp (even a big tube amp.)

6.) There are occasionally used Apogees available within your budget. You may find them a bit off the beaten path in popularity, but not in looks or sonics! And they're coming back for two reasons: first the company has been re-started, and second, we now have amplifiers that are easily up to the take of driving them.

Drubin, my remark about low level listening with Maggies might not apply to the small(er) models, I don't know because I haven't spent time with any of them.

With the right amplification, they do stand up and sing nicely at higher levels. At lower levels, the ones I'm familiar with sort of thin out at the top and from the lower midrange on down; making it a perfect candidate for a preamp or receiver with a "loudness" control contour circuit.

Philojet, you are right about the Quad however low listening richness is a quality that extents to all electrostats IMO.