The table runner looks great!! Anyone would be happy to receive it,
Do not over think this - This is my take - there are others that would cringe and some others that would agree. I only prewash Flannel - never precuts. They will all shrink and it is my philosophy that they will all shrink within a few % of one another Except flannel which can shrink way more.
If you have also washed the finished product then whatever shrinkage was going to happen- it has happened. I do however tell people that they should wash with like colors and in cool to warm water and dry on med heat.