This is designed to use one screw to hold scale model cars. Went with single-screw countersunk mount to enable show-park mode. f3d file included if you want to adjust hole quantity/position/size. 

The wall mount as it is currently sized can hold cars 1.6mm longer than the original as the interior side of the walls has been reduced by 0.8mm to 1.2mm. 

I printed the wall mount using PETG at 0.2mm layer height and 0.4mm nozzle. No supports should be required. I used a skirt, but that was probably overkill.