I've recently made this top. the instructions say, "Sew together strips, using your longest 2 1/2" strips and a precise 1/4" seam. 3 sets of each will probably be enough. 1st dark, light, 2nd dark light, dark chosen for centre, light 3rd dark, a light, 4th dark" .
I understood this to mean that I made (at least) 3 strips using the longest pieces I cut from the shirts, dont forget that you are using 5 dark shirts, One colour is chosed for the centre, the other 4 I numbered 1,2,3,4. I made the following strips using the longest pieces :- Dark#1, Light, Dark#2; Light, Centre Dark, Light; Dark #3 Light, Dark#4 . These strips are then subcut 2 1/2" wide you will need 24 of each colourway to make the 24 blocks. Hope this helps.
Lesley