V bit lettering

In onShape I’ve made signs by using the text tool and removing. I want to use a vBit to carve the text. The problem I’m having is that after looking at the tutorial I need a centre line to be able to do that which will add lots of CAD work. Is there a way to be able to select the letter in KiriMoto to make it work?

The trace operation is designed to do this. It’s easy if the groove has a single line on the bottom in the model.