Seems like this 'elbows in, elbows out, etc' is the common advice given, but I'm sceptical if changing anything regarding hand placement can affect which head it hits at all.
Dips are just another form of close-grip presses. Rope pressdowns just change the palm positioning. Reverse single-arm cable pressdowns are just an isolated movement to get a slightly better contraction if you don't feel it in regular pressdowns, which alot don't. But do these work the lateral head moreso? That's the question, which I doubt you'll find a credible answer for.