My sister would like a chevron quilt for her wedding present. I haven't done HST's before and I'm having trouble calculating yardage. I know they have to be bigger than the finish size to work out right, but I'm not sure how to do this. The quilt will be 90x110 when finished. Here's my "draft".

She didn't like the look of the chevrons close together, so I put an extra row in between each zig zag bit. I was wondering if I could just put strips in between instead of doing squares. Anyway, any help would be appreciated.