I mounted mine on top of the P1P using some roughly 2" risers (I cannot find the original model). I try and keep the AMS as far forward as i can, but i dont think it would be a huge issue to keep it towards the back. I do use this passthrough on the back of the P1P to help keep the cables a bit lower, but they do still rub up against the bottom of the AMS at times i think.
There are some nice wallmount options out there though, and also some stacking mounts that go alongside the printer, that allow you to have more than 1 AMS. Really it comes down to your space, and personal preference.