It's a matter of boots and degree. On my old race boots, it was easiest to have a slight supporting effect from the boot fronts, but I was only slightly leaned forward; I wasn't leaning way over the front. On my new Crossmax 10s, the forward lean is a little less and it's easiest just to stand with knees only slightly bent.
I find I get the most shushing speed with an ever-so-slight rear weight bias; too much rear or front bias causes that part of the ski to resist too much.
I think that IFF you are going to not have any pressure on your heel, you will be more stable if you are forward enough to feel contact on the tounges; you will probably feel more in control with three pressure points, tounge, ball and little ball, than with just two points (ball and little-toe). However for me I somehow feel the whole edge of the ski, and indeed the whole ski. I'm not aware of when my nervous system became integrated with the ski's, and I don't know where the nerves are in the ski, nor how they go through the ski-boot-foot interface, but that's what it feels like.
PS. I have one contact point, the inside of my boot. My entire foot is always in snug contact with the entire inside of my boots, though pressure may vary from point to point.