Advice on teeth/flaps to get under opponents?

[Team Invade]

I'd go for design 1 (no surprises there!) and I think we've proven on Explosion (as many others have) that design works. The whole arm on Explosion is made out of bent 3mm Hardox, so the only welding is on brackets and supports underneath. This is what makes the lip pretty strong. We've never had any trouble with it getting buckled at normal events, but it did happen once at RoboChallenge, which is why we use a spinner flipper arm with no lip for fights with spinners.

The robot which I currently reckon to be the hardest to get under, Kronic, also uses this design.