Here's how I modified the bracket that came with my MAC 4-1 so I could use the factory center stand. This is for a '71 CB500, but the idea is the same for just about any bike.
One trick I like to do is attach a rubber bumper of some sort. I dig through my jar-o'-goodies in the garage and find something. A rubber sleeve from some shocks, a large gasket,etc. This one is a piece of rubber that I cut off of a crank case breather. I like to drill a counter sunk hole in the rubber (using a large drill bit or an abrasive cylinder on my Dremel tool) so that the nut/bolt don't hit the center stand. Just drill the "foot" of the bracket to fit whatever nut and bolt you use.
The bracket is straight with a 90 degree bend at the bottom. Being straight, it hits the muffler before I could even tighten the nut. I put it in my vice and bent it as needed to clear the muffler and hit the center stand.
I use locking nuts, but I still have to adjust them from time to time. The vibration from the bike and the force of the stand hitting it will eventually cause it to shift some.
