First, congratulations - you have chosen the pick of the range in my (biased) opinion. Your dealer will be able to help you choose when to visit in the build process (the actual schedule, not the one you have been promised right now...).
For me, the most exciting times to visit were:
a) When the rolling chassis and the wooden frame were side by side in the metal shop, with the aluminium panels, doors bonnets etc being hand-made to fit. Take a marker pen and graffiti the ply panels liberally with messages for your great-grandkids when they refurb their inheritance.
b) In the trim shop. To watch these guys work is fascinating - and it's the point at which your car becomes uniquely your spec.
Enjoy the agony of waiting!
