I'm not a great quilter, so take my idea with a grain of salt. What I would do is take the longer side off for a few inches (however many you think you need). I would increase the size of the seam between the chevrons slightly. If you spread it out between several pieces, it won't be noticeable. You're probably talking about 1/2 inch or less. If you spread that between just four units, it's 1/8 inch per seam. If you spread it between 8 chevrons, it's just 1/16th of an inch.
Just measure it and see how much you need to take it in.
bkay