i couldnt figure out how to connect the separate pieces so i just took them into blender and added a boolean to fuse them together by default so i thought i'd upload that for people's use.

it's very difficult to print the 90 without it being fragile unless you're printing it bigger so make sure not to use a brittle filament and print slow. i tried printing it with both sides at 45 degree angles and that didnt work for the cheap PETG i used, i had to reprint with one side flat and one side upright, time will tell how strong that is.

this works better than the 90 degree clip:

https://www.printables.com/model/1037996-pre-connected-adjustable-angle-trellis-framing-cli