Hey thanks for the info Ridgeway and others!
I used the box trick last night on some coho filets and it worked perfectly! I also layed an old blanket over the box for additional insulation and it took about 6 hours to complete. For those interested I use a dry brine. I cover each filet with sugar, salt, black pepper and some dried onion. After that I put the filets in the smoker for one pan of chips and let dry. It's absolutely delicious everytime and best of all you don't have to wait for the meat to marinate.

Thanks again!

RM