Microscope-Crosstable

I found the idea of "bastelfreud" to 3D-print a USB-microscope great -
besides the dovetail. In a first attempt I modified the angle of all dovetails to 60° each (better to file?), but was not convinced about the results - even filing with great accuracy it results simply having too much tolerance and as results parts are wiggling...
So I found a simpler solution, resulting+ with much more precision:
A drill usually has a great hole-precision, without the need to file anything...
But printing holes are normally resulting smaller (about -0,2mm), so ø2mm-holes can be drilled relatively exactly to ±0,01mm diameter (minus the material-flexibility)...
And using bike-spokes with ø2mm diameter this would result in a carriage with greater precision.
But: How to make this rails going smooth?
⇒ Using a trick: If we **drill-enlarge** the printed holes (here with a ø2mm-drill) a bit greater than 2mm (drills normally are a few hunderts mm smaller as there nominal diameter – f.ex. a ø2mm-dr