Needed an angle finder, so here we go.

Redesigned the tool to actually be usable. Perhaps not as nice looking, but clamps together in the 0 degree direction with a nice snap if you print it right.

No extra parts needed, just print in place and break of the bridge tabs at either end once printing is complete. Tolerance of 0.4mm is required along with a pretty big bridge across a 0.35mm height, so you may need to tune your machine if your printer cannot achieve this.

Print bridge with first layer at a 45 degree angle to the direction of the tool (see picture) to achieve a satisfying snap when you close the tool. Tested with 0.2mm layers with no issues.

I'm open to suggestions for improvements, so please leave a comment if you have any ideas!