Rob -
It might be well to remember that very few anglers have the extraordinary angling skills that you have so comparing what your impacts may be to what those of the general angler population's might be would result in grossly underestimating the impacts. My limited experience and observation would seem to indicate that the Canadian estimates of hooking mortality are in the ball park.

I would agree that on waters managed with selective gear restrictions the hooking mortality would likely be lower than those with the general regulation. However agian remember that nearly all the waters to be managed under no wild fish retention are not selective gear waters. Again my observations are that most anglers are fishing with bait, barbs, and/or trebles.

If one truly cares about wild steelhead and wishes to error on the side of the resource than assigning hooking mortality imapcts in the 5 to 10% would seem to me to be prudent.
At least until such times as all fisheries are managed under selective gear restrictions and anglers have demostrated that they will handle the fish with the needed care.

Tight lines
S malma