One way to customize the clusters is by adding letters to make a custom title. Start by opening the PSD file and choosing File > Save As. Name it something new, just so you don’t accidently mess up the original.
Next, move some alpha letters on top of the cluster. Resize them, tilt them, etc., to get the look that you want.
Add some drop shadows to the letters and move the whole thing onto your layout. It will look like the designer made a cluster just for you, and it only took a couple of minutes!