Rolf, thanks for the comments. The spin is actually one that Dave Tugwell built and wanted some views on - I think he's very close to having it right. I don't know whether a bungee or somesuch system would have given me any significant gains, but I understand what you're driving at and I guess we're all always looking for 'tweaks' that might mean a bit of a gain. I'll have a think on it.

Wouter, thanks for your comments, and you're right of course - I did say it wasn't textbook!!!