Get some spin locks
http://www.f-w-c.co.uk/acatalog/Basic_Products.html
and some heat shrink for the hook end in case you contact the roof....
I had some rather long ones on mine the other year.... had a high vis vest cable tied to the bottom rung flapping marking the over hang was followed by a traffic cop most of the way and they never batted an eye lid.... im just unsure how much overhang your allowed