Storyline 360 interactions appear squashed in LearnDash!

Hi, I have put some Storyline 360 interactions into LearnDash.

I want the learner to interact with each interaction within the LearnDash page (i.e. not opening in a new tab or window) - so I have used the 'iFrame' option.

However, all the interactions appear far too small. They do not match the width of images and videos in the course. I've tried changing 'width' to >100% in iFrame settings (as shown in attachment). I also looked for any settings in 'player' in Storyline - I can't find anything to help display them bigger. It is as though there is a lot of empty space on the right and left sides of the interactions.

Any advice would be great - thanks!

Cathy