It depends on what you are trying to do.
If you are running 160's or 220's for **** then IMO the best configuration is an upside down goal post. If you are trying for otter then a circle trigger is a must. If you are trying to avoid otters or trying to catch beaver in 220's or 280's then twist both wires together and move the trigger all the way to one side. Muskrats is doesn't seem to matter much, but if you are still running 110's in runs then I suggest you look into colony traps. They are much faster and you can really clean out a marsh or pond with them.
Also not sure if you are a member here or not, but I would suggest going to
http://iowatrapperstalk.com/. It is one of the best trapping sites out there IMO.