Hi Charles
Squadron wagons tend not to carry anything on the roof so I don't think we have any expertise in this area. I wonder if Scoobynet might be a better place to ask. There are several wagon-oriented threads on there you could try.
__________________
Toyobaru 86 with Cosworth exhaust brakes and supercharger, Cosworth mapping, Eibach lowering springs, OZ alloys, fast road geo and various cosmetics. Great fun!