Good news first - I found a joist for my screen in the perfect place Now, I go to mount the PJ, I realise that I have some practical questions - and not what fixings to use. I have a Optoma HD72i. a) does one calculate the exact distance from the screen and central axis for the lens - or do you simply put the mount on, switch it on, move around until it's spot on the screen then mark the holes? b) I've read that I should avoid any zoom - however, this seems to be manual/optical on the PJ, so not sure why this would be a prob? c) The zoom is a wheel (with a raised ridge in the middle) with +/- either side. Depending on the answer to (b), should I be pushing it fully one way or the other - or trying to judge dead-centre (there is no mark and the ridge is wide)? Thanks, Heeb.