One suggestion I have for those with vacuum wipers, is to add a vacuum storage tank. OEM tanks can be used, or make your own. The OEM tanks tend to be small though. My suggestion is to buy a large one that is used by racers and street rodders. The tanks are used for power brake vacuum storage for engines that have low idle vacuum. Tanks can be mounted under fenders out of sight and have the lines and check valves pretty much hidden. A large tank is a little bigger than a gallon jug, just to give you an idea of the size. You will have to find some one way vacuum check valves and vacuum hose. Lots of extra constant vacuum for operating wipers on those hills. I have vacuum power windows in my Frazer, and when the engine is off the window pump does not supply enough vacuum to open or close the windows quickly. After I added a vacuum storage tank, they work just as if the engine was running. No problem with the vacuum wiper either. They also will work with the engine off, until the vacuum is depleted.