Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:5175342.
I've been through more than my fair share of corner clamps. I actually like and prefer this design. It seems to help get the drawer/box faces flush. But needed a slight modification to work better with pocket holes.
This is my source: https://www.thingiverse.com/thing:4778996 I've only uploaded the files I modified, so you'll need to get the the remaining required files from the original post. I felt that version worked really well. Except with box joint, dove tails and pocket holes. The box joints and dovetails have to be sanded down for the clamp to sit flush, but they need to be assembled, glued, and clamped before sanding. With pocket holes the clamp sits flush, but in some cases block the pocket hole preventing the screws from going in. This remix cuts a cylinder out so the screw heads can get by. Or, you could (as I originally did) just file down the parts so the screw heads can get by. The two cylinders on each side are spaced to correspond with the spacing on a Kreg R3 pocket hole jig.
Does it work with your fancy 520Pro, 720Pro, etc? I don't know. Print it out, test it, and let me know in the comments. Or send me one and I'll test it for you :)
I didn't have the original source files to work, so I made the modifications in TinkerCAD.
The new knob was from another source, but for a different bolt size. I modified it to work with 5/16" hex bolt. It is not necessary. I just don't like the other knob.
Printed with infill triangle: 30% and supports 80 degree Everywhere.
Did you find the little cut outs helpful? You're welcome. Did you find the overall design of the clamp helpful? Thank the original designers.
Hardware: M5 button head bolt - 50mm long M5 nut 5/16" Hex head bolt - 5" long 5/16" nut 5/16" lock nut
Edit: Now that I've uploaded Reverse_90_clamp_body_v2_rotated.stl all the necessary files are available in this post. Except the alternate knob.