Bob,
I don't remember any taper cut on the body blocks on my 28 roadster. Tudor sedans and phaetons had tapered cuts in the rear body blocks. You should be using the long rearmost body blocks, as they distribute the car body weight much better than the short blocks. If you post a picture of the tapered body block, it would be helpful. I believe Ford typically used corded rubber pads that were about 3/16" thick. Old conveyor belt material works well for the rubber pads. BTW, the rubber pads that most model A parts suppliers sell are not correct, they are too thin and don't have cording in them. It would be better to make your own. Give me a call if you don't understand what I am describing.
Rusty Nelson