For castor, bait, or climb out sets: I set the loose jaw in line with the centerline of the intended (or actual) path/approach, and 8-10" underwater. Usually stomp, or dig a bed for the trap adding debris if necessary to bring the trap up/stablize. I also add an upright guide stick at the dog (Dead, never green), and usually the opposite side of the path leaving a 10-12" opening. Occasionally will add a "lifter" to the shallow water side. (Causes them to drop their hindquarters to waddle over the obstruction)
BTW- at established climb outs, one can often see or feel where they have been putting their hind feet for more precise placement. Especially with a steeper bank.
IMHO, depth is more important than distance from shore. Might not be right, but works for me