communicating variables across separate SL files via LMS or SPN

I would like to create a course where I track learner progress (answering questions correctly/incorrectly) using a slider. However, I would like the new lesson to pickup the results of where the learner left off in the last lesson. I am afraid it will be too cumbersome to create all lessons within the same SL file. So for example, if the learner scored 25 at the end of L1, he starts lesson 2 with a score of 25 and then progresses from there. At the end off all the lessons, his score represents what he has earned (and lost) along the way. 

Is there a way that I can develop this by setting a variable that can be picked up by the LMS and then used on another module? I have seen this past post, but there is no additional reference or example of how to javascript and use the database. https://community.articulate.com/discussions/articulate-storyline/pass-variables-between-lessons.  We can either host on our SPN or on LMS.