To the OP: a good auto upholstery shop should be able to read your seats and retain the original covering material. After they have the Sears out of the cat and the covers removed, they can experiment with different amounts of foam and where it is positioned, before putting the covers back on, to get the right fit for you.
Let me translate, as the loss of the EDIT function (which I find frustrating) means the above post won't make sense without editing...
To the Original Poster: A good auto upholstery shop should be able to REMOVE your seats and retain the original covering material. After they have the SEATS out of the CAR and the covers removed, they can experiment with different amounts of foam and where it is positioned, before putting the covers back on, to get the right fit for you.
My comment is that it might be cheaper based on hours worked to find a set of Lotus Elise or Exige seats or Tesla Roadster 2.5 seats that you can slip right in without modification.
MODS - Please restore the EDIT function. I know there was an issue, but please reconsider.