Treating the room is out of the question as it is already too dark and serves as a living room too.
The image I attached is really bad, I am posting another one. There are definitely unpleasant reflections from the white ceiling and the white housing of the screen.
Narrower horizontal viewing angles are not a big factor in my case as the cone we watch from is quite narrow. Hotspotting and losing brightness are my main concerns for going the 0.8 ALR route. The N5 is shooting from almost the minimum distance for the corresponding diagonal and also the fact that this pj is no light cannon.
I came across these reviews:
A guy raving about this Celexon ALR, however this model has no borders and seems rather cheaply made.
Celexon Dynamic Slate ALR Screen review
The other one is a ProjectorCentral ALR screen test. Quite an interesting read. The Elite Darkstar 9 seems to do very well with ceiling reflections and has a very good horizontal viewing angle but quite a poor vertical one (for some reason I overlooked the latter while it is equally important). Also among the least bright in the test as expected with the 0.9 gain.
You are projecting a reasonably sized image (not massive) so I don't think light output should be that much of a concern. The N5 is a bright projector.
Hot spotting might be more of an issue but your mileage will vary. I had some minor hot spotting with my older Draper but 100% preferred it to a normal screen. My 110'' Draper I've used for about 5 5 minutes and weirdly have some off axis viewing from the left side but not much from the right... and again, I'd rather have it than not in my untreated room.
I'm happy to have blacker blacks with a narrow viewing cone and some very mild hot spotting, rather than grey blacks all the time.
If you're from the UK, a second hand draper looks like a no brainer. there was recently a draper sale in the classifields with a 95'' linea electric, 110'' diplomat electric and a 150inch techvision fixed frame all going for bargain prices.