Bench Jigs

I'm building two benches (the sitting kind, not the workbench kind) out of nice 2x4 studs (straight grain fir) and designed and printed these two jigs to help. Unfortunately, I won't be able to finish them before this contest is over so all you've got to go on is the sketch and my janky sample corner joint with only two dowel pins driven in. It held so tight without even needing glue that I didn't bother with the other two pins.

Use these jigs with a 3/8" forstner bit to start the hole with a handheld drill (slow & gentle to not melt the PLA) then use a drill press with the same bit finish the holes and make sure they're straight. Ideally use the jigs to start holes on both sides of the wood and drill halfway through to meet in the middle and minimize tearout. The 4-pin jig is for the 90-degree joints on the upper corners of the bench and I'm using the 1-pin jig to on the bottom of the legs and spacers to align them. The idea is that the pins will line everything up with perfectly square corners so that I'll only need 4 clamps when I glue everything together.

For assembly & glueup, cut 3/8" dowels to the lengths you need and chamfer the ends so they will go into the holes more easily. I'm planning to use 1.25" long pins for the alignment holes (just to line up adjacent pieces) and longer pins for the corner joints to span more than one piece for better strength. The fit is so tight I'm afraid that you can't drive them through too many pieces without cracking them, so I'll probably go with ~3.25" or so. We will see what works when I get to glue up!

EDIT: Added pics of first glued up bench in my workshop.