These are the settings I would use.
Use the pet palette as you go.
First 2 points use the 'flight' option and specify a distance that is a multiple of your tread length.
The next point is a 'winder' at the distance of your flight width.
The back of the landing is another 'winder' point equal to 2 x flight widt + gap (70mm).
Then another 'winder' point using flight width as distance again.
And finally the last point is back to 'flight'.
It may not be exactly what you want.
If you don't want all of the winders coming from the one point and want to space them out more evenly, then add half of your gap width to the landing depth.
Barry.
One of the forum moderators.
Versions 6.5 to 27
i7-10700 @ 2.9Ghz, 32GB ram, GeForce RTX 2060 (6GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11