I got it setup after much saltwater on my floor :(
how high should the water flow into the drainage cup? It's a hang on back skimmer. Should it sit right at the very top but not overflow into the cup?

i have mine to where it gets kinda close to the top but still has an inch or two.. so on dirtier days when it bubbles more it will kinda pop over in to the overflow part... mine actually isn't even really in use for like a week of no cleaning cuz my filter is so good.. but it the tank is dirty it will bubble like crazy.. make sense? anyways also pay attention to water levels as evaporation occurs the level will drop on the skimmer and if you add water it might overflow so always kinda look at it to make sure it's all good.

thanks, I'll lower it a bit from the top just to be safe!

what kind of skimmer besides it being an HOB?

eshopps... it sthe big version of this

http://www.3reef.com/forums/protein-skimmers/eshopps-hob-anyone-have-63482.html

The skimmer cup is a device that holds and works by busting the bubbles the slime than collects to the cup and the outside diameter of the central cone(the opening) and slides down to your collection cup. The water level should be to the point of your bubbles busting right at the top of the opening not quite touching the lid. If it is not at this level it will only keep popping low in the tube and defeat the process of a skimmer.Skimmers like the ocean work by busting so you have to have the bubbles bust above the opening. If you want a more insufficient skimmer than have a lower level you will get a very thick slime but it will take a longer time you should be emptying your cup 2-3 days . This again is only a guide line. Your tanks bio load and feeding will determine how much your skimmer needs empty.

yea. skimmers are great, especially if you have alot of bio diversity my cup stays gunky. as far as the whole whats better wet or dry skim... id say do you want to lose more or less water lol, i havent really noticed a difference visually in my tank if i skim really wet or really dray.. wet just uses up more water IMO. it took my skimmer a while to finally get right like 6 weeks lol. it was tuned in before then but it would fluxuate and then i had to find the level in the tank to keep the water at so it would work right. after that it works like a charm. i run mine more dry, it fills up the cup slower because there is less water in the skimmate and reduces my top offs.