Best way to set panhard bar

[randomhero472]

just put 4" drop coils in the rear, got a new adjustable pitman/panhard bar for the rear, whats the best way to measure to make sure the bar is adjusted right, also should i have bought an angled shim for the rear end to compensate for the drop? oh ya.. will i need to have the truck aligned again if im putting 3" coil in the front?? thanks