I actually made the yellow one first out of a yellow tee. It took longer than I expected (not just because I had to cut four million little circles) because I made my extra ruffly. I guess I should have referred back to the picture/tutorial more often.
The gray one was made from some leftover cotton I had from the clutch I made for our big night out. I was able to cut out many layers of cotton at once (as compared to the jersey from the tee). It went much quicker the second round.
At first I wasn't sure about these necklaces because they are quite different than the ones I usually wear, but it turns out that I really do like them.