I'd be interested to know how you get on with yours - mine has been converted in the same way and heat soak is proving to be a problem, even with a lot of heat shielding. However, that problem may be the slave cylinder - the exhaust is very close.
Next time mine starts suffering from the spongy, ineffective, pedal, I'm going to have a good feel round the clutch master cylinder to see just how hot it feels. If it's not that hot, then the slave cylinder must be the cause, I don't quite know how I'm going to get round that one, if that is the problem, though!
Does anyone know why the single reservoir is used for both systems and if it's possible to change it? I'd be tempted to use DOT5 fluid in the clutch, to help with the heat resistance, but I don't think I want to use it in the braking system. If I was to go down that route, I'd want to fit a smaller reservoir just for the clutch.