That is brilliant to use Bean Bag pellets to fill the duct tape dummy. When I made one of those before I got a mannequin, I used paper towels like a moron. SO MANY ROLLS and it ended up being pricy!
Also be careful with time allotment and how you hang it. You probably know all this but I try to warn everyone I see using such mannequins just in case so they don't mess theirs up like I did mine
My dummy started to warp and the tape would slowly sag and deform under its own weight over time, so laying it down when you are done for the day may be beneficial to preserving it longer. It was mostly around the abdomen and shoulders the tape would slide apart, leaving residues of stickiness and making it inaccurate.
Over time it will likely slip apart anyway, ((Mine at the end of its sad life was a flattened blobby thing even though I stuffed it firmly and used oodles of tape)) but if you are careful it should last you plenty :3