Wet skimming(more air) bubbles up into the waste collector faster, but does take more water out with the waste products.
It takes out more dissolved organics with it though.
Dry skimming(less bubbles) will perculate much more before it pushes up into the waste collector, so you won't get as much skimmate but what you get will be thicker because you're removing more solid waste. Your skimmer will need to be cleaned more often because the sludge buid up inside the skimmer.
The Deltec hob skimmer I had skimmed wet, the skimmate was pretty clear, but the waste smelled so strong it stunk, so it was pulling out nasty stuff.
Don't know if that helps, but lots of successful tanks skimming both ways, so do what works for you.