I got a couple of new pieces today but I'm not completely satisfied!
I've misunderstood how the printing resolution works. I thought it would affect the surface roughness, but not the measurements.

This resulted in too thin material at the connection points

Now I know that it affects the Z-axis, so I understand why the thickness didn't turn out as I thought it would, 1.38 (layer thickness) doesn't divide well with 0.2 (printing resolution)!
I also noticed that I got the wrong measurements of the holes by 0.08 mm, that explains a lot too - learning by doing 😉

Otherwise the bow looks great when assembled

The wheel I drew turned out to be as good as perfect!
However, there could be a little bit more material between the o-ring countersinks and on each side of them. I will probably add another 3 mm on the total thickness

The wheel fits nice and tight to the motor shaft, so no need for a lock screw!

I will get the o-rings in a couple of days, that's why there's no tiers on!

Stay tuned for next update!