I usually run my skimmer (turboflotor) so that the top level of the bubble column is in the tapered tube in the collection cup, maybe 3" from the top of the tube - running like this, if you watch, the foam sort of builds up occasionally and spills over the top.  This gives me dark skimmate, but not very much of it.  Trying to adjust to skim any wetter is usually very sensitive at this point.  
Something I noticed recently is that the bubbles, while very small in the skimmer body and at the bottom of the tapered tube in the collection cup is very small, they form much larger bubbles as they rise up in this tube in the collection cup - I don't have a lot of the really foamy stuff overflowing into the cup - more like mostly big bubbles that rise up to the top of the tube, pop, and the liquid from that bubble then trickles down the outside of the tube into the cup...
My skimmer runs HOB on my fuge at the moment - I'm going to build a new fuge/sump soon that will isolate the skimmer pump to a small chamber.  I do get good water to the fuge/skimmer chamber, though, from a DIY HOB acrylic overflow (thanks to melev's website 

).  So, i think I could do a lot better as far as getting good water to the skimmer, but my setup is probably not the worst, either...
So, back to my real question, about the bubble size - is this large bubble size in the collection cup neck a problem ?  Should I be looking to get more foam coming into the cup, and should I be looking at adjusting the amount of air available to the needlewheel to try to get this result?  Any ideas?
What about the other turboflotor owners - does yours run like this?  Thanks guys...