Fudging.
As long as they are the correct sizes making them equal. If you are talking about the borders. After you measured down the centre of the quilt and go to put it on you find it is too along by half an inch. DONT CUT IT OFF. Pin the ends find the centre of border length and quilt side and pin together . You will find you have a slight loop on the border gently pin centre of each side again and keep until really no loop at all they are pinned equal ie eased in.
Now machine. Hope this helps.