I have heard something similar to this already but how about moving the races forward by a day or two?

Start racing on the Saturday with the last races on the Thursday so as to give another day to deal with the increasingly horrible weather, i.e. the 'Senior' races could happen Thursday with the Friday as the carry over day rather than the Saturday. this could then give the Senior classic guys a chance to get to the other race I have been told they goto after the Manx.