This is design for the Shen Drones Geyser and Squirt (V1/V2/V3), for the Squirt there are no standoffs that could match the rear screw holes are just zip tied down, this has worked fine and I am yet to break a zip tie despite some hard crashes.
Guide for 3D printing the gimbal design here.
Files on Thingiverse: https://www.thingiverse.com/thing:4957896
UPDATE: This design is compatible with the 20mm Universal Mount.
Medlin Drone 