3-5mm is standard, but if I remember this books rightly they're fairly cheaply bound (it's been a while since I've seen my copy of the one in that post, saddle

3-5mm is standard, but if I remember this books rightly they're fairly cheaply bound (it's been a while since I've seen my copy of the one in that post, saddle stitched or stapled). Assuming a 5mm bleed, you can have at most 1cm cut in from the edge, which is substantial.