Re-X Carriage (Titan Aero extruder, Re-D-Bot) - THINNER Motor Holder

I found that the original motor holder was too thick by about 2mm, and my screws wouldn't reach the stepper (with either the original Titan or with the Aero cover.)

At 3mm, the updated base is still plenty thick when printed with .8 shell or thicker. Infill is up to you (50% works nicely), but I'd stick with the OP recommendation of 100%.