Please welcome Eyoyo Underwater Fishing Cameras.https://amzn.to/3siEgXn
Not sure how close to the Three Forks area you are, but willow creek reservoir near Harrison has big browns. It's hit or miss on how hot the bite can be.
Most the reservoirs here have the big browns you seek. Any lake you that you know of has browns has those big fish. I usually end up running into a few on jigging raps and small white jigs both tipped with maggots. Have also heard guys on Ennis and some of the bigger lakes will fish sucker fillet strips on jigs on the bottom and pull some reel giants. Good luck out there!
I'm with Hutchmt....Willow Creek Res is where I would go if I wanted to catch a 24"+ brown through the ice. Used to pull some real hogs out of there when I lived in Three Forks. Also, some big rainbows in there, so either way you should catch nice fish. Caught most on a black leach imitation about 1' off bottom. They like to cruise the shoreline.
I would not suggest that you eat browns. They feed on many things in the ecosystem that contain high levels of mercury, lead, and arsenic. Ex, crayfish, snails, exoskeleton creatures...Most Montana waters are full of these due to geo thermal issues and mining waste. Rainbow and perch tent to feed on more plankton and foods with less toxics. The only time that I regularly keep fish to eat is during ice season. Check out the consumption warnings on the waters you fish for food.