It’s too close to mount on the front of the gantry. Should I put spacers behind the plate?
From what it looks like, if you put spacers behind the gantry plate, you will not only create more leverage on your gantry set up (which may not be a problem) but could you create a mount for your ball screw ends that for between your uprights?
I spotted a 3d printer in one of your pictures, maybe draw up some end mounts and print them out first