Hi Anna, have you seen the quilts a number of TQS members made for Sue and Jack Garman? We'd asked for 7 inches live area and unfinished sizes of 9 inches square, and for the most part, that's what we got, but there were some odd sizes, so Liz Whitehead came up with an easy way to handle that. Here's the Flickr site where we posted photos:
http://www.flickr.com/groups/suegfriendshipquilt/
If you click on "more" under the first set of images, then go to page 2, you can see Liz's layouts from EQ. One of the things we did was to make some small filler blocks to fill in the spaces where the block sizes weren't lining up. We also had a couple of blocks stick into the border (see the lower left corner of Jack's quilt) and that helped with sizing, too. in the EQ layouts, it looks like there is sashing, but we didn't use any. One of Liz's other tricks was to offset the columns so that we didn't have to worry about lining up seams! Good luck! I'll be eager to see what you come up with! Best wishes, Robin