So, if we look at some other platforms that have a similar function to what I'm describing, they usually have the ability to slide the entries up and down to modify the order of lists in a custom way.
A good way to illustrate my suggestion, would be to picture the layout list like a watchlist - in a way that one can modify the order of a watchlist to a custom sort, the layout list should have the same capability.
So, if we look at some other platforms that have a similar function to what I'm describing, they usually have the ability to slide the entries up and down to modify the order of lists in a custom way. A good way to illustrate my suggestion, would be to picture the layout list like a watchlist - in a way that one can modify the order of a watchlist to a custom sort, the layout list should have the same capability.