every week i replace the water from the skim with enough salt to keep the salt and water levels steady. instead of taking a gallon out at once i take it out over 2 or so weeks
It really doesn't matter if its wet or dry skim. It depends on the dry weight if you removed all moisture from the skimmate.
I personally prefer skimming towards the wet side because I find skimming dry builds up all that gunk on the neck of the skimmer, instead of inside the cup.
Somewhere not far behind "what salt is best?" and "what is the best light bulb?" in the pantheon of "you will find no agreement and little hard data" reef dilemmas resides "is it better to skim wet or dry?"
IMO it is personal preference as opposed to any real tangible husbandry benefit either way.