You're right, you can definitely go bigger, however, what's most important is what is best for your tastes. Period. End of story. I just wanted to reiterate that predicting the perfect size is near impossible if this is your first go around. There is in fact someone very recently who had his screen size predicted. He built custom shelving/cabinetry around the allotted space. When he fired the pic at the wall, he realized he much preferred a larger size than what he had allowed. He ended up covering up the cabinetry, wasting his time and money. Just another example of how hard it is to predict, and the possible pitfalls.
The best size, or compromise thereof, will also be based on the quality of your source material, and the AR you typically will watch with. Most of my movies, by far, have smaller AR than 16:9 for instance. Also, I exclusively watch hidef. If I put on a DVD, even upconverted by Anchor Bay, with very good PQ (say, a Peter Jackson flick), its still rather unbearable and too unforgiving on my 159" screen. YMMV. A good bluray transfer will leave you picking up your jaw from the floor.
While excellent black levels are really nice to have, I would be careful on how much you spend on that sort of thing if you are not going to control your light. Dark walls are best, period, and I do mean all of your walls, including ceiling, and even the back wall. Ok, very few go to such extent, but my point is that it will all help out. For instance, I use two large Ikea rugs in the front, and they helped tremendously. Ok, what I want to say is that a midlevel PJ in a good room will outperform a top notch PJ in a bad room. Contrast will decrease exponentially with the increase of ambient & reflected light.
The screen I use is a DaLite High Power. I've already mentioned the compromises, namely, the narrower viewing cone, and the necessity of having the PJ mounted as close to the angle of the viewers heads. Whether that means table mounted, shelf mounted, or ceiling mounted with a longer pipe. (btw, a little cool tip: some people extend the pipe as the bulb ages for increased brightness).
This is due to the retro reflective properties; the screen reflects the image back towards where the light is coming from. (emulsified glass beads). While this helps its ambient light rejection, you would very much like to have all viewers within 20 degrees. I think I just about succeeded with that, or very very close to, with two rows of four. So, its not like its impossible, but it really depends on the setup. If for instance the pool table is very close, if you're on one extreme end, it might look dim. OTOH, if the pool table is very far away, the off axis angle represented by any end of the pool table will not be as obtuse.
Basically, the screen is multiplying your brightness up to 3x, depending on how close the PJ is to your head. It does so in a uniform matter, everything is properly raised at the same level. This allows someone like me to use a 3k PJ that doesn't have a light cannon price tag, and get my huge screen still. Some other strengths of this material are virtually no hotspotting, disappearing of screen, heavy material that is resistant to waving, among others I think. Oh yeah, its extremely affordable. My screen is over 75 sq ft, and I perhaps unnecessarily added the CSR feature, and custom ordered in black, both for additional money, and its still less than 1k shipped. The screen, at this size, is very heavy (I presume due to the glass) and it took three people to mount.
hope that helps.
btw, as much I dig my screen, I've only heard good things about Carada here, and I take what BMXTRIX recommends very seriously. I will not say that one is better than the other, but if he recommends it very strongly, so would I.