All the old documents are still here;
https://issuu.com/mark77a/docs
Here are the direct links, recommendable seems to combine these two
https://issuu.com/mark77a/docs/strida1-owners-manual
https://issuu.com/mark77a/docs/strida3-owners-manual
and don’t miss that one:
https://issuu.com/mark77a/docs/strida_tips_v3b_from_mark
That should answer many of your questions - we are still here for the remaining