Actually I'm riding in a similar 'race' in November too - ebikes allowed but can't 'win'. The distance is ok - 125kms (78 miles) but there is 2,700m (8,860 ft) of climbing. IME climbing is by far the biggest drain on the batteries. I don't think I could make it on just the internal + RE, but I will borrow a RE from a friend and hope that is enough. Any thoughts on the best way to manage the 2 RE's on such a ride?