Just got an LG AN110B - should I get a grey or white screen?

Hi

I have just purchased the LG AN110B wall mount DLP projector and I am trying to decide wich screen to get. I have trawled the forums for information and I think my head will explode.
I want a 234cm wide screen and with a top budget of £200 I have come down to a choice of 2, the Sapphire park lane (£200) or the grey wolf 2 (£127) both at CVS media. If anyone could offer me any advice based on the following setup.
1. The LG AN110B is wall mounted so basically points straight at the screen. Does this have any effect on my screen decision as I have read the angle of the projector appears to impact the grey wolf image.
2. We will be sitting mainly 5.5 metres from the screen. Does this affect my decision.
3. While one sofa points straight at the screen the other is at right angles to the screen at the side. Will this badly affect the view on a grey wolf.
4. While we have black out blinds at the windows the walls are a cream colour so I presume this is not the ideal setting for a projection room. Does this mean I should go one way or the other.

Thanks in anticpation of your help.