Bathtub drain

Hi,
I am installing a bathtub. I really want to install a 2 inch p trap, but I do not have alot of room. Can I contort the p-trap in any shape? Secondly, to avoid a s-trap, how short can the trap arm be? In order for me to use a 2 inch p trap, I need to contort the ptrap and have a 6 inch trap arm. Is this ok?

Thanks,

Dan