Knocking out the teeth on overflow?

[Son Of Skyline]

Does anybody have any experience knocking out the "teeth" on their overflow? I did a test run on my new tank today and found out that the top of my overflow doesn't even come close to being able to handle the flow of a Mag12. I'm wondering if I need to worry about animals getting sucked down into the sump or if it usually isn't a problem. I ask because I have seen someone run without any grill or teeth on their overflow but I never asked whether it was a good idea or not. I thought about using a dremel to deepen the slots, but judging by how quickly the water flowed over, I think I'd need VERY deep slots to make it work and I think it would just look strange. Thanks in advance!

One more thing...I noticed a slight leak in my overflow bulkhead. Do I need to seal it with silicone or should I just tighten it down a little more? Do bulkheads normally need to be siliconed?