After some more time, some issues became more clear, that the focus travel was too slow. I designed a multistart thread and ordered a new prototype of the aluminum tube.
It works well so far.
There was also some issues with the horizontal tubes being wobbly so I printed a two piece clamp that holds them snugly, and it works much better.
I'm considering making it available with or without the stand, for a lower cost option. I won't be able to run a Kickstarter for this until I ship the items for the last one I ran back in January/February.