I think the best advice I can give is be consistant. The quilt may end up being a little smaller than the pattern if you don't get a scant 1/4 but if all the seams are the same I don't think it will matter. I think Bargello calls for narrower seams because on some of the very narrow pieces, you don't want the seam allowances to overlap. I have a good 1/4 foot and I move my needle position over one space when A pattern calls for a scant 1/4.