Not sure how big the little squares are on your graph paper, but if its 1/4" I'd bring that out a bit on your welt. 3/8ths is the minimum I use, up to nearly 1/2 for some applications. This allows for some grinding room when you get the leather all together. Its amazing how quick you run out of space when truing up an edge.
I use plain manilla folder for my patterns so I'm not so distracted by the squares. Its the draftsman in me.