Thanks cth4242, I missed that one because I'm from film and video editing and scrolling is up-down movement and roll is horizontal movement kkkk.
So, they have achieved a very decent solution for a text chain with predictable lenght (I uses almost same maths for my movement). The problem is using tags chains that returns text chains with very different lenght every time. And I want to keep the loop tight without emptys from end to begining the new one. I'll keep investigating. Thanks for your time!