bigdaddyball wrote:Is there a rule on where the umpire can set ?
There's no rule.
It's recommended that the PU position themselves behind the catcher and between the batter and the catcher. PU's inside ear should be in line with the inside edge of the plate. Eyes should be between the batter and the inside corner of home plate; positioned at the top of the strike zone. This type of positioning is referred to as working the "SLOT".
PU's feet should be at least shoulder width apart with his/her foot slightly forward. This is referred to as a "heel/toe" stance.
There's more involved but this should give a general idea.