You are following the right sequence i.e. connect first, power up projector first and then laptop. Power down should be the exact reverse but not as critical; don't move the projector before the fan has stopped running and only then switch off. Most projectors now have more than one input. As already pointed out by others, calibration will always be an issue. My recommendation based on experience is that you use projector port in 1 for your own pc/laptop and port 2 for the 'foreign/guest' pc. Although possible, I would not connect both laptops simultaneously to the projector. I once had an experience with a mac that caused us to reboot both the projector and our laptop to sort out the ghost image that the mac had left on the projector. I concur therefore with the advice to do a dry run with the mac first before the big night and to set that up first if at all possible. If the programme content does not allow that, then create a tea break to do the second set up. Good luck Roel