I had a smoker porter reach the NHC finals(41) that had 20% smoked malt (I smoked moist Maris Otter for about 1 hour over a very small fire(140 degrees). I called it Campfire Porter. I used hickory, apple and peach wood. It was really bold but still balanced according to the score sheets. I think you need at least 10% to have lasting smoke character since it does fade with time. Twenty percent is as assertive as I can tolerate with home smoked malt. Weyermann Rauch malt isn't nearly as strong so I think you could use more.
BTW- I'm coming to Huntsville next week, Keith. Will you be at the brewery on Saturday? If so, I'd like to stop by.