Scaling issues on launch / resume

Hi, I'm new here. I'm creating a Storyline player template. I've eliminated the skin so that all the controls overlap the slide content. I did this with JS in the slide master (mostly by modifying margins). However, the slide doesn't scale properly to the JS adjustments upon launch and resume (results vary based on browser size). What I think is happening is that the slide is loading before the JS can run. Refreshing the slide (seekbar replay, resizing the browser, jumping slides etc) instantly snaps it into the right place. 

I've attached screens. Any thoughts on how to resolve this?