I finally got fed up with trying to tune SU carbs for non-standard configurations (I'm too mean to hire a rolling road session every time I make a change) so decided to switch over to fuel injection, based on the SPi throttle body and manifold:
I developed my own ECU over that last 6 months or so and eventually got the car running really well - far better that I've ever had on a carb engine. There's a detailed description here:
If you've been wondering about Megasquirt or similar, then I'd say go for it - its worth it even just to get rid of the choke.
Incidentally the car's got a 1098 engine in it at the moment - I wonder how many fuel injected 1098 engines there are?