If it really looks okay, as you said, the recipient will probably never even think about it as less than perfect. After all, the rest of the quilt was done on a sewing machine wasn't it. Just be careful that it is all pinned as straight as it can be and do the short side of the smallest one first. If you are not positive, do the corners by hand and the rest on the sewing machine. The corners are always the hardest for me to get just right.
sincerely
sueinbarre