Uhmm depends. You can get "flatter" with a carve. So like If I do a big sweeping carve left I can throw my weight to the back right, open my shoulders, and at that point my chest if facing back up the hill. Doing that I can actually get it perfectly flat (like my head is not above my waist/legs, or below it, it's a perfect line).
But honestly don't try to learn it by carving, it will make it harder for when you don't want to carve and you won't really get the right "feel for it".
Yeah, feet kick out towards 10 oclock, and your left shoulder opens up towards up hill. Helps to grab japan too, it gives you the right motion and feeling with your right hand sweeping forwards as you open up with your left hand.
I could never do flat spins on the trampoline, until after I learned it on the snow. I got the flat rotation first try on snow, it's much easier with the way you're taking off and landing to do it on snow.