maybe 2 or 3 of the top leaves in middle, but you want to retain area of coverage...
don't remove all leaves from any 1 node. Light hits leaves and it reacts -- not the bud sites. Light hitting leaves at local nodes will power that growth better than trucking in ATP through the phloem. Whether you speak of buds or avoiding stretch.
If light readily penetrates, don't bother and save the leaf. stick to those general guidelines, and you can't screw it up.
leave at least 1-2 leaves at any one node
provide light to deeper regions of plant where good nugs can grow... don't bother trying to illimunate the bottom node if it's buried and can't ever grow anything worthwhile even if it had light.
familiarity with your equipment and the yield to expect will help you pick out that zone of good buds and how to prune/defoliate other places to focus more resources on the happy-zone.