[Conal]

Scott
I will be riding with Ching on the 10th, and will be carrying 4 batteries. I have read all the posts and can understand the many points of view.
My reasoning is simple. I do not know how far 3 or 4 batteries will take me. I do not think that carrying the third extra battery will make that much difference to the overall weight and would be annoyed (with myself) if, only carrying two extra batteries, I approached a hill towards the end of the route and ran out of power.
In a way the fact that we are riding a few days before the other event on a similar route is a good idea as this "trial run" will be of help to others. If on our feedback we give distance, speed, how we used power assist, individual weights, and other details, then this can be used constructively to ensure that people know how many batteries to take on the second event, or at least the power output we used.
Conal