This is exactly what I was thinking I would do!
Originally Posted by
dublb
Here's what I would do. I would measure the biggest one & add black borders onto the others till they are all the same size. Then I'd use red sashing as I sewed 'em together. Then I'd make a small red border then a wide black border to finish it off. Now you do what you want & it'll be great. 
best,
d