You should be able to lay out all your actions and still have a lot of space if you use 2 crossbar pallets. Try to keep stuff grouped together in a way that makes sense to you. In my case, using MNK as an example, I have my combo's first step on R2 + X, second steps on R2 + Square and circle, and Third step on R2 + Triangle. R1 takes me to my second set which in those slots instead use AoE skills laid out the same way.

There are a ton of customization options for gamepad, like you can have a crossbar set only show up when in battle, you can disable bars you don't want to show up when cycling with R1 alone, etc.