In Scapple, each note is automatically sized based on how much text you type in. But in Scrivener’s Freeform Corkboard mode, you must set the size of the index cards, and each one will be that size. This wastes space because you will have index cards with less text and lots of empty blank space.
Is there any way to customize the size of individual index cards so each is only as big as the amount of text inside?
In both the Linear Corkboard and Freeform Corkboard the index card size determines the size for all cards. As far as I can tell, individual index cards are not self-sizing based on card content. The cards mirrored the physical objects that were (or are still ) used. However, you make a good point about space and the potential to optimize the cards in the digital world. Sounds like a feature request.
To scale your Index Cards on the Corkboard View automatically, set the number of cards you need to see and tick the checkbox Size to Fit Editor in the Corkboard Settings in the footer of a Corkboard. Now, when you resize the Editor by pulling the vertical dividers between Binder, Editor or Inspector, your Index cards grow or shrink to fill the entire Editor pane.
This won’t resize the Index Cards to the amount of text on the cards, though.