You added a pretty good degree of difficulty with the 12" minimum...........Had a couple of slams this year, one on the White and the other on the Norfork..........I'm not a guide but fish a fair amount on the White.........Have yet to catch a 12" Brookie but suspect they are fairly few and far between......There are some smaller Cutties in the White also but more 12's in my opinion but not near as many as there once were........Just catch all 4 for the Slam and accept it or not........There are some good guides on this site and all are very capable........but this may not be near as easy as it might seem

Shooter