custom length snapping

[glro]

I know there is a debate about the usefullness of length snapping in sketchup.
But it has been used efficiently by scaffplan:
https://www.youtube.com/watch?v=B5MPRqQPV3U

at about 1:50

From what i red, there is no way to customise sketchup length snapping though ruby, except changing the step.

Is there a way to do it?
for example make the cursor jump to 0.3 / 0.5 / 0.7 / 1.0 / 1.5 / 2.0... m, which are usual length of scaffolding components?

[glro]

length snapping does not get a lot of interest, but i add information on how i solved my problem, in case of somebody might find it useful in the future...

in my case length snapping was not the solution

The cursor movement is not changed; instead, a message is shown based upon the movement of the mouse, so the user can decide when it is time to stop moving the mouse and click the second point
https://vimeo.com/939627532?share=copy

this is low level programming, but it works.