I just finished making my great-niece a T-shirt quilt for graduation and I did sort of a field fit. I cut out the piece of shirt that I wanted to use with as much extra fabric around it that I could. When I had every thing cut out I did a trial layout. I tried to line up the ones that looked like they would be the same width. Then I worked on making my columns the same length. I did have to piece some of the blocks with some of the leftover material from the shirts they were cut from and trim some up. Then I cut my iron on interfacing to a somewhat common width size and what ever length size. I did not have a pattern so I did do some trimming here and there. I did look at some of the T-shirt quilt sites and got ideas from there. I think it turned out okay but my niece and grandniece were pleased and everyone at the graduation party raved about it.