JetJester:
I have a Tandem Island that I haul on top of our Yukon Denali, the distance between the roof racks is maybe 4 ft, and they are rated to 250 lbs. The TI is 18 1/2 ft long (longer than vehicle). What I did was purchase the Malone Seawing racks with the Stinger combo which is an extension (see
www.maloneautoracks.com) . In order to provide more stability I placed one of the stingers facing forward and the other facing backwards. I then took a 8 inch long piece of pool noodle wrapped in 3M electrical tape tied under each stinger (too help support the weight, and to keep them from flopping in the wind). With this setup I have 4 support points with about 8 feet of support length (6-7 ft on your Subaru). It is very stable the boat doesn't rock front to back when I go over railroad tracks like it used to without the stingers. On short trips I don't tie the front of the boats down but on longer trips I do. With 4 support points I get very little hull distortion. We haul one or two boats up on the roof pretty much every weekend ( so does pretty much everyone else in Sarasota, (lots of Kayakers), we go mostly around Florida's west coast and Key West all year round. Unfortunately I can't go through the Mcdonalds drive through with the boats on the car, and have actually lost weight. I'm not a big guy, and don't have any problems loading the TI by myself ( I load it up and go out every weekend, often both Saturdays and Sundays). Hope this helps
Bob