Full disclosure, I did read all of the other post so there may be some repeating. The biggest things I see is that you're skiing narrow. It looks like you're rushing to make your turns. I know you're not in a course but this is setting you up for slack line as you're often going faster than the boat when you turn. I'll come back to this in a sec.
The other thing I see is on both sides (although more pronounced coming from your offside), you're not pulling through the wakes. If you establish your angle at the finish of your turn, work on carrying it through the wakes. Ideally you should be initiating your edge change at the centre line but just to avoid changing too early and hitting the first wake on a flat ski, I'd say pull through the second wake and then make your edge change.
Now I'll come back to not rushing your turn. Once you've made that edge change, let the ski carry out till you're wider on the boat. I've even heard of people taping marks on the side of their boats where the rope needs to get to at each line length to be at "buoy width".
I always tell people that slalom skiing isn't about the turn itself. It makes a big spray and looks impressive so people think that's the important part. In reality, the turn is just our only way to change our direction, the real work and hard part in slalom skiing is what happens behind the boat!
Yes, you should always be working on your body position, even when you're not making turns or in the course. Even when you're sitting in the water or just standing on your ski, however, I don't feel that I'm justified to give tips on body positioning!