3D printed strap adapters for the CB1100 mounting pegs

[LayerCake_imp]

how much weight will they hold? 3d printed stuff i have no experience with

How much they will be able to hold depends on print settings and material you could print them in titanium ... probably expensive and not worth it but you could.
That's why on the page I mention you should test them and make sure you are comfortable with them as I can give zero guaranties about how they will behave on your bike.
For me printed in PETG on a Prusa i3 MK3 they are a snug fit no room to add a bump they just would not fit with one anymore. They are not meant to be left on the bike they're meant to stay with the luggage as prolonged exposure to the elements is probably not ideal for most plastics even if this print is pretty chunky.