Congratulations on your Twin Grandbabies!
Adding to the above thoughts .... consider the shrink factor before you start sewing.
For me, I would pre-wash everything before starting, so that most of the shrinkage is dealt with.
Otherwise your quilts could shrink considerably and thus become a lot smaller.
RE Retayne ... the treatment works great, but check the product info, as I am pretty sure that it says that the treatment is cancelled if washed with hot water after.