Supporting ducts horizontally seems pretty straight forward--just a loop of strapping underneath to support it. What about when the duct runs vertically? Do you use the same kind of strapping but attach it to the duct with screws, or is there more to it?
If you put a couple of sheet metal screws in the joints, and tape them with foil tape, you should be able to do a 5 foot vertical rise with support at the roof boot or where you contact the rafters. You could use straps, but usually the boot if sized properly will be fine if the bottom of the run is supported well.