I have a couple of the vertical hotbars which I've set keyboard hotkeys to activate (I use CTRL 1-4 for one side and ALT 1-4 on the other, kinda FFXI style). That's where I keep some long cooldown abilities and Limit Break, or stances that I'm only going to need to use once. That's freed up some space on my XHBs. Then yeah, I have another set up just to monitor cooldowns on stuff I can't immediately see on my main bar.