My floor bump is a little less noticeable because I had this thick padding under the matting. I don't know where you get this, it was just in the parts shed.
The material John mentions is called "jute carpet underlayment". Easily found available from lots of online sellers (and I'm sure you could find it locally) in various sizes from cut pieces to large rolls. Cut to fit. It also adds an increase in insulating and sound deadening to your cab.
