So I thought I'd try dual extrusion with a single nozzle to see how realistic it is and it totally works. I've seen other Y-guides (credited for inspiration), but somehow I didn't like either of those for various reasons and had to design my own, which is, luckily, not so complex.
This is one is a single-piece printing with no support, pretty customizable if needed, but since it uses threads.scad library I didn't make it customizable by customizer (not that it's impossible, but too much hassle).
How to print with it is a totally different story depends on your firmware, slicer, etc. Guess you're on your own here.
If you take a scad file make sure you do the final render with
You absolutely don't want support within the part here.