When saving spell sets, only mem the spells you want to switch to, leave other spell slots empty. This makes it quicker to swap spell sets, because it doesn't have to reload the entire spell bar if you happen to have other spells memmed at the time.
Here is my default spell bar.
Using this hotkey I can load the spell set I made earlier.
Here is the end result, changing only a few spells out so I can main heal.
