I would go with a Chief. An arm and a leg isn't 150 bucks to hang a projector the way you want to. Most of all, it used standard high-pressure piping which you can get at Lowes or Home Depot and have custom cut to the exact length you need. So, instead of worrying about an inch or to, you can get it dead on, get it adjusted perfectly, and after putting the projector up, you can hang by your arms from it and it will be incredibly solid (not recommeded).
Really, they are a superior product and worth the bit of extra cash for the stability, adjustability, and reliability that they offer. RPA series - just get it.