It depends on how much quilting you want to do. I like to do a free motion specific design in the snowballs to emphasise them. Certainly 1/4" out from the seam is an option. there are many stencils that would be easy and would work in spaces such as these. Several years ago i made a hexagon (similar to snowball) from print and matching solids. I machine quilted a motif in the solids and 1/4" in the prints as you would not see the design on the print. Check on line for the companies that sell quilting stencils and see what is available.