Re: angular error: Did you check the geometry of your printers? You'll need just a really square ruler - but don't print that on a suspect machine! It will lead to certified errors.
I made about 20 chain members now in PLA. Improving and optimizing the anti-warp strategies and fine-tuning nozzle temp and cooling parameters on my printer again (a task that will never end...) , they come out flawless, snap together with some enforced persuasion, but then mvoe together optimally - after some grinding-in of the remaining slice pattern protrusions. Just exercise the chain for some minutes, and it will run fine.
Great work, rotoscan! Thanks!