If they are very old, their existing size would be a uniqueness to me. Like the Vintage machines, these blocks tell their own story about the times and conditions they may have been made in. I would do anything I could to leave them as they are. I agree with the block sizing/stretching and I really like the idea of having the odd sized blocks bordered by themselves. I just wouldn't be able to cut them. And if they are very, very, very, very old they are even more unique.
((Can someone on this board look at the photo and maybe date the material?)))