you don't say what size the desired quilt will be , but 40 shirts is quite a few! Like Feline said, the quilt you posted does end up with partial seams, so I'd suggest you do like she says and try to use dimensions that will allow you to make either equal size blocks in rows or columns. And definitely use scratch paper. I've made quite a few that are similar to what she is wanting--I usually measure all the t-shirt logos (add some space around each) and figure out what I have to work with. Then I use my outline of my quilt and place the blocks in it. Graph paper allows you to figure out the width/length of sashings too. Good luck, these can be a little tricky. If you have EQ7 or 8 (I'm not familiar with the earlier versions) you can use the unequal blocks layout,but don't add in color to the design or you lose the grid (I always make them 1") to figure out sashing sizes.