My opinion for casting… 2 guys 14' is a squeeze. I did it for years, but it is tricky. 2 guys in a 16 is pretty comfy. 3 guys even an 18' can be tight depending on the layout. Would definitely go 18' or bigger for 3. Long rods and big baits make muskies a different ballgame than other types of fishing. If trolling, 3 in a 16 is just fine.

To be close to comfortable with three it takes 18 feet. Smaller can work if casting in any direction is an option but in my experience that isn't very often when muskie fishing. If you need to go smaller then a tiller is a good option to open the floor.