Issues with index_lms.html vs.story.html and our tincan tracking

We use Storyline 3, and we have implemented our own tincan tracking, which works great.  A couple of years ago, Articulate changed its publishing scheme to use index_lms.html instead of story.html

https://articulate.com/support/article/Storyline-New-Launch-File-for-Tin-Can-API-Courses

So for any output published with newer versions, we use index_lms.html as our launch point, and it works fine.

But we are now trying to integrate with a 3rd party, and are trying to use Rustici Content Controller with  RXD (Cross domain) option, as we must run in our own domain.  For a launch point, I have to use story.html, since index_lms.html doesn't run -- when we just run index_lms.html from a browser, it shows the first slide and just hangs.  And if we use story.html as a launch point, either in any browser, or within SCORM Cloud, the course runs fine, but our tracking does not run at all.

I notice that the new story.html file has tinCanPresent: false, while index_lms.html has tinCanPresent: true, but just changing that is not enough to get our tracking running.  Story.html changed extensively between the pre-index_lms.html Articulate version and the post-index_lms.html versions.

Is there a way around this?  Is there a way to get index_lms.html to run from a browser?

Kind of a long narrative, but thanks a lot for any insight.