Call me OCD, but for sleeves I like my letters to be all the same size (width and height).
It looks pretty like that.
I use the graph paper tool (keyboard shortcut "D") to draw a graph of 1 column and as many rows as the max number of letters I plan to use. Then break apart.
Next, I type of my word, break apart, size all the letters to the same width and height numerically using the toolbar at the top of the app (make sure you've "unlocked" the dimensions or it will keep trying to scale proportionally).
After that, I put one letter per graph box, and align each to the to the center of it's box (keyboard shortcut "C" after you have your box and letter selected).
Voila, perfectly awesome looking sleeve text. Font-wise, I like Rockwell Extra Bold for athletic sleeves.
I know, it SOUNDS like a lot of steps, but it's really not bad once you've done it once through, and the results are awesome.