I have had a problem with Amass XT150s in that they are slightly too big to fit in the “surface mount” 3D prints (designed by gliderpilot I think). I have had to expand the 3d printed parts: x & y 109%, then had to file down part of the “base” to make it fit the rectangular hole in the plate. However I did find the 3d parts were also too small for the nuts and bolts so it looks like the STL file model needs changing a bit??