I still do alot of hand seeding with my bag seeder, I was tired of the strap cutting into my shoulder when the bag was full. Went to the dollar store and picked up one of the kids floatie things for the pool, cut it to lengthand slid the strap though it, no more strap cutting into my shoulder.
Watch out for what kind of pipe insulation you get. Most has a slit to open it up to go on the pipe. Sure you can seal it but I doubt it would hold up top the flex and bending.