Screen Goo is a good product, but you can do the same with many of the DIY methods described on the AVS DIY screen forum. I spent years trying various DIY paint methods with paints you can buy at your local Home Improvement store. I've used rolling and spraying methods. Yes you can get a great result that will rival commercial screens costing hundreds/thousands more. However, you need to be willing to put some time and testing and practice to get good results.
My last screen was a AVSforum favorite called SM/MMud (Silver Metalic/MississippiMud) which gave me great results, but not until I spent months practicing my painting methods. If I were you, I would go with a UPW Flat White (Ultra Pure White) if your set on painting. You do NOT want any texture on your walls.
You need to keep in mind that a gray screen should only be used if you projector has poor contrast. Today's newer projectors do not suffer from this, so you really don't need a gray or "high contrast" screen. Actually, you will lose color vibrance the more gray you go. On the flipside, if you go with a high power screen (high gain) you'll have more pop and color to the image, but contrast (grays) will suffer. Your best bet if you get a decent projector, is to go with a Matte White 1.0 gain screen. Matte white has been around in the screen industry for many decades. That is what most theaters use.
There are other DIY options, like building a frame from wood, and wrapping with Black Out Cloth. BO Cloth is rubbery drapery lining that will not let any light pass through it, one side is smooth matte white. Or, if you have a Home Depot or Menards around, go to the paneling aisle and get some Parkland Plastics Durotherm Lite panels. They come standard in 4ft x 8ft x 5/16" thich core. They are very light weight and one side is smooth white and gives killer results.
All your answers are on AVSforum and ProjectorCentral as I've mentioned in prior responses.
