Oligosaccharides are hard. I’ve been looking for good tools to create 3D structures for them for a while. (Hoping something will get into Avo v2)
A search turned up:
https://www.biotopics.co.uk/jsmol/amylose.html
https://www.biotopics.co.uk/jsmol/amylopectin.html
Looking through those webpages, it looks like you can get the PDB files to download:
https://www.biotopics.co.uk/jsmol/molecules/amyloseplus.mol
https://www.biotopics.co.uk/jsmol/molecules/amylopectin84.pdb
If you look into the source, you’ll see JavaScript that calls load molecules/amylose.mol etc. for molecules on that page.
It’s definitely on my radar to get glycan / saccharide building into future versions.