Slug,

Did you catch a beaver yet? Go ahead and set the 330's like North 40 suggested. Don't get too crazy making a picket fence with guide sticks. All you want a beaver to do is dive and hit the trigger. You don't have to guide him for 10 feet to do that. I will warn you that if you educate them they will be really tough to catch so hopefully you will get them the first time they set off the trap. If they are using those runs you should be able to catch something. Give it a try. Catching beaver is fun - no pun intended (I'm lying). You really should not have a dog issue with water sets.