Wiimote Project

I have a question about buying a projector screen. Something like this

http://www.rentourprojectors.com/images/projector%20screen.jpg

I will install it to the wall, but (like all projector screens do) it moves lightly to the wall side and comes back. that because projection screens are not solid, they just hold from 1 side. The other side its on the air...

So while the projection screen is mooving am i gonna be able to write? Wiimote gonna detect the IR writing while its slightly moves?

IF the detection its ok with little movement then i am ok.

If not i can give it back, shortly, and take an ink  whiteboard? on that size

Should i purchase a short throw projector or its not needed? One like this
 http://www.projectorpoint.co.uk/projectors/BenQ_MP525ST.html

Would it be better so it wont be any heads while i am in front of the smart board or it doesnt matter to be a short throw projector and go ahead with a nornal one? Like this

http://www.benq.com/products/Projector/?product=1578

Standard Infrared Pen
Item # STD-IRP               

"The Groove" Infrared Pen
Item # GRV-IRP               

"The Spot" Wiimote Tripod Mount
Item # SPT-ACC               

Mini Tripod
Item # TRI-ACC         
      
USB Mini Bluetooth Dongle
Item # USB-ACC               

Wiimote Rechargeable Battery Pack
Item # RBP-ACC            
   
USB AC Power Adapter
Item # ACA-ACC               

Smoothboard v1.6
Item # SMB-SW

+ an Wiiremote motion plus ? (do i need a motion plus? or the normal one?)

1)Do i need something else?

2)What the best place to buy them? i found this  website

http://www.wiiteachers.com/