Spoke to Hi Spec who were very helpful and warned me about potential problems with heat dissipation. I may need to think about adding ducting and we had a good conversation about surface area, disc width and increased numbers of vanes in the discs.

Anyway, the smaller piston needs to lead so each caliper has the smaller piston at the bottom and the larger piston at the top.

Geoff at Hi Spec also suggested a higher temp pad than the Ferodo DS3000 - a pad from Performance Friction which I think is an American outfit. I may try these later in the season if the DS3000 struggles to cope. All this to come.

Charlie