I wouldn't go with a Dell Projector, I'd instead go with the Benq sh910 or Optoma th1060p if I were going for a DLP in a bar (but I think you should also consider LCD, even though the PQ won't be as good for Sports):
See this article for the DLP comparison: http://www.projectorcentral.com/benq_sh910_optoma_th1060p_projector_review.htm
The Da-Lite High Power screen has a narrow viewing cone and too many people will get less than 1.3 gain unless the viewing area is very narrow and long, so I seriously doubt this will be appropriate for your bar.
These super bright DLP's are going to be 3x color wheels, and a few people are going to see RBE and be annoyed by it I would think. For LCD's, you can get business crossover projectors or some Epsons that can do 3000+ lumens. Keep in mind the ratings dont mean much, generally if it says 4,500 lumens, you will get about 3000 to 4000 lumens in a watchable torch mode and maybe 2000 lumens in calibrated mode.
As far as the screen, depends on how big you are going with it, I'd do at least 1.5 gain and then surround the screen with an overhang or build a small platform around it to counter ambient light (if you can). You might also consider building the screen yourself and using DIY paints (it isn't that hard), then you have a better choice of paint mixings to get the exact gain uniformity you need.
If you go to certain Bass Pro Shops, go look at their video games in the back that are hooked to a projector, they took this to the extreme and built it inside its own area. Now I don't mean to that extreme, I just mean a basic frame to block SOME direct light from hitting the screen. You can essentially create a shade effect over the screen to increase contrast.
I would probably try to find a uniform gain screen in the range of 1.5 to 3.0, depending on various factors (how far will screen be from projector so how bad is hotspotting, etc...).