Tee is meant to be worn with little or no positive ease in the bust. Choose the size closest to your bust measurement; if in-between sizes, I would suggest making the larger size.
More information can be found on the pattern page.
For awhile I have had multiple colors of Elsebeth Lavold Silky Wool waiting in my stash. More than a few times I played 'let's create a color story' and laid them on the floor in various combinations. Finally I ended up with the colors that matched a sunburst guitar and fell in love. This bright combination creates a nice gradient effect, I think.
The Silky Wool is a great yarn for warm weather; it is lightweight and soft and best of all, it doesn't give me immense wrist pain like cotton does. When designing warm weather garments I have to get creative with my yarn choices since I try to avoid yarns that are purely made of plant fibers.
The Sunburst Tee is a bit shorter than the tees in style at the moment, mostly because I wanted something to wear with skirts that I didn't have to tuck in. The long t-shirt over a skirt just doesn't look right on me, so a short tee works out better. The length is easy to adjust if you want a longer tee. Check out some of my pattern tester's projects on Ravelry to see their lovely versions.