My 180 reef has an ASM G4 (rated for 350 gallons) and a SWC 160 (rated for 130 gallons or something)
My 180 FOWLR has an ASM G4X (rated at 450 gallons)
my 125 reef has an ASM G4. (again, rated @ 350 gallons)
I tend to also overskim but I like to keep my tanks stocked to the brim full of fish and LOTS of skimming is one of the tools in my box to allow me to do this.
Also, I bought each G4 for $200 used (including shipping) I found them on craigslist, and paid the people via pay pal and got them in the mail. A bit risky but worked great. Did the same for the giant G4X (looks 2x as big) but it was $300 used. All of them work fantastic and I have never had issues. Great skimmers.
Vertex will sometimes go on sale, I got the 180i for $300 from BRS on black Friday, but I think the 150 would be perfect and with 900 lph of air draw a heavy stocked 100 would be about perfect.
I am looking into skimmers for my new build and I have been reading some good reviews on the Aquamaxx Cone-Co in sump. Worth looking at, you should look at the Cone-CO2 for your size tank. I am sure you'll get some great suggestions on here.
Good Luck!
I would go with a Bubble Magnus Curve 5 or 7. I was having an issue with my 9, but since I think I straightened it out. My tank is three weeks old and it's pulling green and black crap right out.
Plus 1000 on all the ASM suggestions. I have a vertex alpha 250, a tunze, a cadlights, a couple of different reef octopus. I have ran many over the years. I still miss the ole g3 I gave a preacher friend a few years ago.