Need STL File for 3D Printed Junction Box Cover Ended

I need an STL file to print an electrical junction box cover similar to the one attached to this post, but with some modifications: 1) The back plate should remain the same; 2) The device screw holes need to be 60mm center to center, with minimum four (preferably six) perimeter layers around each hole in the final print; 3) The device screw holes need to be rotated in orientation so they are on the horizontal and vertical axes (instead of diagonal as in the sample); 4) The large opening in the middle needs to be made as large as possible without compromising the strength of the screw hole anchors, which can protrude from the inner diameter of the center hole; 5) The center hole should be at least 60mm in diameter; 6) The outer diameter of the ring should be whatever it needs to be to retain strength in the part, but in no case should it be larger than about 72mm; 7) The ring with the device mounting screw holes should protrude 1/2” from the flat junction box cover; 8) The device screw holes should be sized to accept threaded inserts. See sketch for the new dimensions of the mud ring on the back plate. read less