hmmmm, the row already sewn together is too short? some quilters get creative and just add a bit of the same color on the end. then where ever else it needs it .sprinkle the fixes around and they wont' be too noticeable. if everything isn't sewn into rows perhaps you can trim each block down to the smallest one. then everything would fit. just sit and think it over. i'm sure you will be able to work things out.