Don't till. Bermuda is mowed at the mower's lowest setting. When there are any imperfections in the surface of the soil, the mower wheels will fall in and scalp the grass. The imperfections come from inconsistent settling of the fluffy rototilled soil.

Where do you live?

How would you characterize your soil? Sandy? Clayey? Something else?

Is there grass there already?

Is there any shade in the area you want to plant?

Is anything growing in the area now?

I would sod rather than seed, but I think I told you that already...