Custom Screen Size
Would someone please provide examples of when you would use a custom screen size? The only information I have found is that the maximum custom size is 2,047 x 2,047.
I use a long width and a short height often when I am designing Storyline content that will specifically be shown inside of a Rise Storyline block. Most Rise blocks tend to be more of a banner than a block so doing so helps the Storyline content fit more seamlessly into Rise.
Here is an example Rise course with a wide and short Storyline "banner" block example.
https://360.articulate.com/review/content/b56569f8-4679-4c5c-a937-738eb98cc3fa/reviewTo Owen's point. Putting SL in Rise may open up other possibilities. I once had a request for and interactive Org Chart in Rise. So I built it in SL and made the Slide size very tall and narrow so there was room for all of the levels in the organization.
