Hello. I have a question about my screen size. Should I place the projector back as far as I need to get the size that I want without using the zoom or is it ok to put it closer and use the zoom?

Thanks

Zoom is fine. You may run into minor issues when you push it to the absolute extreme but most people don't. About half way between full wide and full zoom is a good place to put it. That way you can keep some lumens available that would not be there if you put your PJ way back.