I haven't got round to buying a touch tool yet, but was planning to. Now I see this post.

At the moment I bring the spinning tool down manually, one stepper notch at a time, until it cuts. I think the method you guys described is also manually bring the tool down (just not spinning). So for my case where I can see the workpiece I don't see any advantage. Is that correct?

The touch tools you buy are sprung I think, so you drive the tool down into them? To make one I think you just need a contact on a sprung base and then either some addon software? or maybe it's already in Mach3?