Checking the TCDS for the GCBC model I see with a 128 pound Sorenson spray rig installed the max gross weight is increased to 2325 pounds. With placards in view of the pilot prohibiting spins and aerobatics. Max weight of chemical based on airplane weight and balance but not to exceed 800 pounds.
So, If I get a restricted category airworthiness certificate, install a Sorenson spray rig I can boost the gross weight my GCBC to 2343 pounds. That would give me an additional 561 pounds useful load, (wheel pants removed) Wheel pants weight 14 pounds accodring to the TCDS.
And with a slight modification the spray tank can become a cargo pod.
Things that really make you go "HUMMMMMMM"