Ok, you want to print dummy in scale 500%+.
First problem you will face - you can't just assemble it. Joints just cracks. Yes, hot air could be used to make joints soft. But.., why??
Okay, you can try joints+. That works, but that joints too loose to keep robot standing with increased weight.
Second problem - hands. In this scale default hands looks awkward, definitely needed movable hands.
Then you'll want to change head. There are so many cool heads.
Also, armour tolerance, they are different in original and scaled dummy.
So, here is solution:

Joints is most valuable part of scaled dummy. To provide greater flexibility, gaps were added in the most stressed areas. Also, this gaps adds walls by slicer. Walls adds more clamping force, which provides better effect on friction.
Also, fuzzy skin effect added to all movable parts to increase friction (all that yellow stuff in slicer).
This solution was carefully tested and approved to be effective:

Result of test and experiments - failed joints

Dummy's beta hand were used
This model has print-in-place fingers (500% scale is not easy to assemble)
Modified finger joints, separated palm-finger joints are separate details to allow easy change of most wearing joints
This model is in scale 500% of original Dummy 13.
Model contains 3 separate files. Frame, armour and hands. Eye is separate part of armour and should be glued. I prefer glow-in-dark plastic for armour.
Reviews and prints of my scaled models:
Please, check my other stuff on makerworld, printables, share your print and happy printing!
The author remixed this model.
- Fully rebuild hands. It's compilation of easy13 posable hands and dummy 13 posable hands. Fingers made to be printed in place. Separated finger-palm joints
- Joints rebuilt to meet scaled model requirements: added ability to stretch more while keeping force without cracking.
- Changed head, modified to have detachable eye
- All joints modified with fuzzy skin effect, to add more grip
- Modified armour to match scale (different scale - different tolerances)
- All that was result of printing in 500% scale and fixing non-working parts.