Its quite simple, If you have clean, broken in (Running long enough to produce skimmate) skimmer and compare it to the organic matter that is in your cup after one hour, and dry out the wet skimate you will roughly see that same amount of organics removed. but that's only part of the issue. Once a skimmer has been producing dry skimmate for over a week you will see a direct drop off of skimmate due to bubbles breaking on the way out of the skimmer,(this is due to inefficient bubble rise) Hence the organic build on the skimmer walls, to rectify this one would encompass a wet neck skimmer, to keep it clean, but it doses nothing for efficiency, the bubbles are still breaking. Not the third part of the issue, the type of skimmate and what it contains. this is where the is great diversity. The normal skimmer is only 12% efficient some are as low as 3% and the best under tank units scored 18%. Now Dont take these numbers and times them by the % they are lacking. As a bubble rises it needs to be in a state of uncontacted medium with other bubbles, not continually mixed and striped of there organics. it takes about 20 seconds for a bubble to become completely absorbent and unbreakable shell, it is at this stage organics rapidly are attracted to the bubble, the longer the bubble is in contact with the water, the more organics are removed, again this is amount of times the percent , the bubble starts to attract heavy metals in their last stages of full development, slowing the bubble further and collecting inorganic compounds.
So what does this have to do with wet vs dry skimmate? first it keeps your skimmer cleaner, which allows more organics removed, since I know only a few people clean there entire skimmer once a week, wet skimming is more beneficial they dry skimming. Adding of FSW over a longer period of time is better than dumping in 10-20% all at once.
Now if the skimmer is above 30 feet tall, then you would have ideal bubble rise and then you can see the difference of metals removed in the skimmate, a large amount research papers are done on this subject due to this is how your local sewer treatment plant works.