I changed the proportions of the polaroids so they have thinner tops and sides. I almost ruined them though, by trying to take a short cut and trim several down at the same time in a stack. Oh boy, SO not a good idea! The bumps caused by so many seams one on top of the other meant the rotary cutter wouldn't go through them properly, which caused several to skew and when I stopped to see how they were going it looked like some wild animal had been savaging them along the edges, and many of the borders were cut on an angle. Despair! Rending of hair and cursing of stupidity! Luckily, there was enough on all of them to create a straight edge with the blue sashing and I actually like the thin borders I ended up with. It wasn't very good for my blood pressure though.
I used blue strips of various widths for the sashing, ranging from 3-1.5cm. I'd say the 3cm gave the most flexibility in terms of placement and wonkiness, but having wide on one side and thinner on the other was also quite useful for breaking up the tendency for each polaroid to line up with the others. Thin-thin didn't work. I ended up laying them all out on the cutting mat, making sure the edges of each row extended over some arbitrary line, and then I cut along those lines. This meant all the blocks matched perfectly, although they're not all the same size. I think there are pros and cons to doing it this way. On the plus side all the blocks match up and sewing them together was a breeze. I also like that the seams are scattered about to a degree so it's not too grid-like. On the other hand, it is slightly random-looking and there are seams everywhere!
I used Kona for the solid blue and I have to say it's really not the nicest fabric. Sure there are bazillions of colours and all that, but the weave is so coarse and cheap-looking it's quite off-putting. I need to try some different manufacturers I think. Spotlight's solids have a very nice hand and come in a decent enough range of colours, but I've found if you iron them repeatedly across a point where the seam is quite thick the fabric wears quickly and the colour fades so I'm not sure what their lasting power is.
ETA: Thanks for all the comments about solids. If anyone is interested in the various types around Little Miss Shabby has a great run-down here.
