My 2 cents on your question. I am in no way an expert.
On the subject of screen size.
I dont know if your doing 16:9 or Anamorphic. The ratio may affect your lumens as well if your trying to stretch a consumer level projector to the max (someone more into Anamorphic than me can correct me on that). Not only is Lumens an issue with a 13' screen size. You may have screen door effect as well. At 13' you may want a higher caliber of projector than a normal consumer. If your tool box consist of a check book and nothing else then maybe you will be ok.
On simulating commercial grade 3D
There is a review on projector central regarding a polarized lens mounted on the front of the projector which eliminates viewers needing active shutter glasses. You still need passive glasses though. This setup gets you closer to the "at the movies" effect for 3D. However this may change up your game plan. They suggest a siver screen for reduced hot spots. At the time of the review the adapter required DLP projectors only. Upon looking at the manufacturers site this may have recently changed to include LCD as well.
I dont know how new the technology is for a consumer, but it seems the local theater is using the same setup. I was at an IMAX 3D showing of Prometheus. I noticed they were using a silver screen. After the previews were over, I noticed a shadow over the screen and thats when the 3D visuals started. Then I remember that commercial grade polarizers move in front of the commercial projector (kinda like a CD rom tray moving infront of a projector lens if you will). Then there was an IMAX promotion/commercial that is was a DLP picture. BINGO!!!
Here is the link to the review.