You have four bars with 20 spaces each. What I do is place my primary class skills, set skills and such on one bar, secondary skills and elites on another bar, third bar holds everything that I use regardless of class.
The fourth bar is kept hidden.
When I swap secondary class, I hide the original secondary bar, and show the 4th bar, that becomes my 'new' secondary bar that I set it up the same way with secondary skills elites and whatever I need for that class combo.
Since only one bar is active at a time, I have them both in the same position, so there's no 'hunting' when you change class.
It's an extra step, but when switching main, the bars change anyway so it only needs to be done when changing secondary alone, and it's pretty quick, pull menu up, uncheck one bar and check the other
Some things I've become used to having in a certain location, so my secondary bars have some duplicated things on them
