If you can't figure out a good solution go back where you bought your sink and ask questions. A standard disposal should be able to fit. With a sloped drain opening your plumbing might be interesting underneath.
The old deck plate had bolts and screwed in to the two outer holes, like a dummy I threw it away. The new deck plate just uses plumbers putty, no matter how much I use it still comes loose. Now I would like to find just the deck plate for my sink that I can bolt down. Any one know where is a...