I'm finally taking up building the D-Bot 3D printer. I was going through the excellent build guide and some of the parts listed in there. I noticed that none of the gantries have eccentric spacers in them and they all have an oval hole to adjust the screw snugness with the rails. I though I'd modify this and add eccentric spacers there. This brings me to my question. First, what is the spacing from the centre of the mini V-wheel sitting on one side of a 2040 V-slot to the centre of the other mini V-wheel on the other side of the 2040? I measured it to 52mm and wanted someone experienced to verify this. 52mm is when the wheels are snug on the rails. Second, there is a gantry parallel to this one that attaches on the other side of the V-slot. Since there are now holes for eccentric spacers on this one would there be same sized holes on the other one? Essentially would the two plates mirror each other? (see image).