Depends on the scene. Generally speaking, Slockie picks out clothing, environment, and other assets, though we often look for them together. If I have a specific look, series of actions, etc. in mind then yes, they go into the script. In some cases I'll specifically link the asset I want to see in the scene, though that's much less common. In even rarer instances, I'll write out the blocking of the scene, though that's usually to set up something that happens in the scene so Slockie doesn't have characters in the wrong position for that to play out properly.
The only thing I'm consistently detailed on positioning is during sex scenes, especially when multiple LIs are involved. I typically block the entire thing, with details on changes in position as they progress. The exception here is when it transitions into a montage, during which Slockie has free rein to add whatever he'd like (within reason; I've had to veto puppet sex more times than I can count - Slockie has a weird fetish for marionettes).
Slockie is final arbiter on the visuals, though, so sometimes he overrules my suggestions to go with something different. I'd say 95% of the time his idea is the better choice, but in that other 5% I usually make my case and we end up in agreement. It's a very collaborative effort on pretty much all fronts except the coding (of which I know only the bare basics).
