Dude, bolt-on notches are really shady, if you ask me.
Think about it: You're cutting away a peice of your frame..YOUR FRAME...and BOLTing on a plate.
If you're gonna notch it, I would HIGHLY suggest just going with a full-boxed notch. You can get one from Alter Images for about $100. It's worth it. Otherwise, you'll ride around everyday wondering if your frame is going to snap.