Continuous not self-intersected single line text?

Hi everyone!

I'm making a defenition for a laser cutter and labels must be a Continuous not self-intersected single lines without close contours. For the reason that closed contours and self-intersections would be holes, and separate numbers take to much time to cut on this machine.

Im trying to make it using Fabtools engreave and than make a polyline from division points. But of course result is not what i need.

In the example screenshots number 12 is what i need.

But this method didn't work with every number.

Any suggestions?

Thanks!