I found another okay farm place. You can only do it once, and can’t roll a specific weapon for effect. But there was like 5 enemies and 2 were legendary every single time. In far harbor, doing the captains dance. Save before dropping meat in the water. I ended up with a instigating handmade rifle for one of them and called it good lol
There may be a way to save at the right moment to reroll a weapon. Because there are 2 times you place meat to spawn them. So saving at the right moment may work, but I’m not good at figuring that out. I just farm the old fashioned way