I've looked at a couple different peoples mini notch, and was wondering if a brace on top of the frame is needed. I see some people weld a metal strap on top of the frame.

 

I cant see it hurting it. Box the open side too

 

If you use a thick enough piece for the bottom I don't see a reason for an upper brace. I used 1/4" plate for mine since I only cut up to the bottom of the rubber plug on the outside of the frame. That notched it just under 2".

 

I've got a 3" plate already built out of 1/4 plate. Looks like the bolt in kits you buy, just weld in. Just looking for advice, doing it shortly.