welshman599, I've been pondering the crockpot dilemma for a couple days and I think I may have found a solution:
Model 5S Super Trapp Quiet Muffler
The Model 5S is designed for engines from 10 to 200 HP. Recommended for engines from 10 HP to 100HP where minimum exhaust noise is required (Resonator required for noise reduction) and for larger engines where space is limited. Supplements an existing muffler where minimum noise is critical. Use 1 disc per 7 HP. Discs are sold in package of 3. USDA Forest Approved spark arrestor No. T-101.
I would recommend for white beans/navy beans, use 1 disc. For pintos, use a full pack of three discs. I hope this helps. If you need anymore info, don't hesitate to ask.