I went back and reread your entire posting, and so am editing.
1) I have never had either my Woodstock Fireview or my Woodstock Progress Hybrid have any blackening of the glass when burning, at any burn rate, unless I have had wet wood in the stove. If I have had wet wood in the stove, the window will get some darkening almost immediately I go into cat mode, but this will almost entirely, if not entirely, disappear once I get to a hot burn. If there is any residue darkness, and I don't want to wait a few days until I need to burn hot, the darkness wipes off very easily, The glass is not an issue with Woodstock stoves.
2) BTU calculator on this site says that for a 13 x 25 room in your zone you need from 3900 (very tight, modern insulation, warmish out) to 10,400 BTU's (average insulation, cold out) for your stove room alone, assuming door is closed and no heat flows to any other room, depending on level of tightness and insulation and outdoor temp. Woodstove requirement chart on the Woodstock site indicates that for your zone and square footage you require in the order of 50,000 to 60,000 BTU output to heat a 2000 sq ft home assuming 8 foot ceiling height, average insulation, and ability to get air to flow through your home. There is also a good description of the factors that influence the heating of a home, and what you can expect with different set ups... 50,000 to 60,000 BTUs calls for a stove with very good output. Either of Woodstock's two largest stoves would probably be alright, and perhaps also the Keystone, although I would lean toward the PH because of your difficulty in moving heat and the fact that you are just slightly larger than the (very conservative ) rating Woodstock gives the Fireview. The low end of cat output for the Fireview is about 10,000 BTU, the PH about 12,000 BTU . High ends of each maybe 55,000 and 80,000 plus.
3) There is no need to choose between a stove that will gve you an overnight burn and a stove that will fit in the room. Any cat stove large enough to heat your home will give you an overnight burn, and any cat stove will fit in your room, whether you are talking about actual size or BTU output. There isn't too much difference in size of the stoves, as someone has pointed out. There is a difference in clearance requirements. For assistance in sizing in your room now, to give you an idea of the space you will need, mark on the floor an area five feet wide along the wall and four feet from the wall going into the room, with the two outer corners cut off at a 45 degree angle. That is about the size of Woodstock's largest prefab hearthpad, and is both big enough to take just about any cat stove, and has a sufficient R-value to meet any requirements. So that will tell you the footprint. The other factor is visual impact. Different stove design and relatively minor difference in stove size can yield quite a difference in how they impact a room. If you look at the recent thread that is entitled something about removing or replacing a Fireview, you will see posted very good before and after photos of a Fireview and a Progress Hybrid installed on the same pad in the same location. They take exactly the same amount of space but have a very different feel and impact. The PH is bigger but has lower clearances, and is top rather than rear vented, so the two stoves sit on exactly the same hearth pad with exactly the same chimney (Woodstock actually made certain that would be so, to make the install of the larger stove easy because they knew a fair number of their customers were switching from Woodstock's previous largest stove to the new now much larger stove --another example of great customer service. They worked and tweeked really hard at the end, and did repeated testing, until they got the stove to have clearances that would make the transition zero cost other than the stove itself)ANYWAY...the point is that the stoves are quite different in size and heat output, but take exactly the same floor print in the room....but the Progress Hybrid is a significantly larger stove and has a greater visual impact on the room...and also looks very different.
A great incentive to try a Woodstock if you are really worried that any stove will be too much is that they will let you burn for 6 months and if you are not satisfied for ANY reason, will take the stove back for full refund, no questions asked (which tells you that very few people are unhappy with their stoves!). This would allow you to buy one of their good sized stoves (Fireview or Keystone) and, if you found it put out too much or too little (and I think that is also a possibilty here) heat, you could return it after six months and, if you liked the Woodstock product, exchange it for a smaller or larger stove as was appropriate for your setting...or just keep the money and do something else if you preferred. And your new stove would slip right into your previous installation....
4) Woodstock stoves are super efficient (especially the Progress Hybrid), glass stays clean, and they require no upkeep, hardly even chimney cleaning, except very occasional cleaning of the cat (once a year or less with the Fireview), which is super easy and takes no longer than removing the ash from the firebox, which one does on a regular basis. The stove are super sturdy, beautiful and amazingly well built. Cat needs replacing maybe every 6 years, costs about $125, takes about 10 minutes. Save way more than that much in wood over the 6 years from having a cat. You don't run into any other maintenance, and the stoves need no blowers and are totally free of dependence on electricity. They also lend themselves very well to stovetop cooking. They are sold directly from the manufacturer only, service and quality are legendary. Don't know if these were the soapstone stoves your wife didn't like. If not, get her to look at the site. Most people are very impressed with the appearance of the stoves. And the feel of the gentle heat radiating off a soapstone stove is hard to describe, the closest I can come is to say it feels as if you are sitting in a very sunny window...the heat heats you, not the room, and very soothingly.
Oh - and someone who just installed a Fireview posted that on one of his very first burns he reloaded the stove at about 5 AM, went to work, came home more than 12 hours later and the stove was still warm...
I think that addresses most of your questions.
Good luck in your choice.