How overstocked am I?

[Teeb]

I have a 75g tank with around an extra 20g in the sump/fuge running an older octo 90g skimmer. I really don't want to pass up the smoking deal that R2U has on a pair of Helfrechi's, but I know there's a little too much life in the tank right now.

Fish in the tank are:

2 Percs ~1.5"
2 Black Percs ~2"
1 Scopas Tang ~4"
1 Kole Tang ~3"
1 Coral Beauty ~3.5"
1 Pygmy Angel ~1.5"
1 Red Coris Wrasse ~4"
1 Lawnmower Blenny ~2.5"
1 Watchman Goby ~2"
1 Flame Hawkfish ~2"
1 Copperband Butterfly ~4"
1 Green Chromis ~1.5"


I think I need a bigger skimmer.