It depends on what mount you use. It will be easier to mount the 3010 after the screen to get perfect alignment. But, if you have a mount that can adjust up/down and left/ right to give you some play when the screen arrives you could do itt first. MOST mounts do not have this adjustability. By up/down I am referring to raising and lowering the projector, not tilt up/down which it will need as well. By left right I mean slide the projector left or right not rotate, which of course it needs too.