Here's a couple of ideas for C and R cradles...I've been using them for trout fishing in Wa for several years. There are many guides in AK who are using them in the C and R sections of the Bristol Bay drainages for big rainbows. Heck, even the Canookies are ahead of us in this field as they have been using them for big Muskies for years.

http://www.fieldandstream.com/fieldstream/gear/finder/article/0,13440,195793,00.html

http://www.fishontario.com/articles/muskie-cradle/

Personally I don't buy into the "I can't release a fish over the side of the boat because its too rough". Bring the fish next to the boat, put it in the bag if you have to stabilize it and use your god given peepers to discern if that fish has an adipose. Instead of trying salvage your 5-cent hook, 50-cent slider rig, or dime corkie...cut the line. No need to bring it into the boat....if your life is in jeapordy just cut the line and be on your way. Just my rant.