I don't think you can use a block with cleat on the tramp. The cleating angle changes as the traveller is eased making it difficult to cleat and release. I tried a swivel cleat with alum disc under the tramp for my spanner and it was a big fizzer for that reason.
I've seen it done successfully mounted on the tramp with a cut-in-half tennis ball with the cleat attached through the middle. Ball pads the cleat and holds it upright as it swivels back and forth.
