I owned the company that lined gearbox bands and cones for Listers and relined the same for several of the larger parts suppliers. You should remember that both bands and cones run "wet" that is to say in oil and therefore any material you use MUST be a specialised "in oil" friction material. Normal woven material will not work, in fact may degrade and gum up your box completely.
The material on the cones is a special woven material, nominally 3.2mm thick, but is ground after bonding (thermal setting) to a cone template. The material on the band is a paper material, imported from the US, and was 1mm thick.
I do not want to sound too down, but this is not a job for the amateur. If you have problems contact me and I can point you in the right direction.
Alan