Seems to me, the effect of osmosis will equalize its self as far as salt levels are concerned. By not oversalting your brine, and utilizing other flavors I canâ€™t imagine a 12-24 hr brine would hurt anything. A tip that has served me well is to taste your brine before you apply it to your turkey. If itâ€™s too salty for you, itâ€™s probably too salty for Mr. Gobble.
You can read the lables and find turkeys that aren't brined, pumped or water added if posible - fresh turkeys sometimes frozen. If you do a brine you can still add flavors you want. Just stay away from the Butterball type and that sort.
I'm with dee-jay ,brine a turkey with no additives ,in Canada the Butterball brand is injected with vegatable oil,source out a bird with no additives such as a plain grade A or Ut ,in Canada it is law to have a UFT label stating an additives ,attached to any cut of meat that is not 100 % natural,hope this helps ,T-bone ,( Tim.)