Servos...
Dave, the servos I used were 29.5mm x 11.6mm x 30.2mm. They fitted (just) without cutting the lugs off. I would say that this is the biggest servo you would want to use. Kevin's model flew well with the Turnigy digitals. They are cheaper and smaller (but you'll have to wait for delivery). I'll certainly be interested to see how they perform over time, in the same way that I'll be interested to see how my servos hold up.