Made a decision on skimmers this afternoon.
I don't think I previously mentioned it, but I had been running an ATB 840v2 on my old 150g system. That skimmer was used for a few weeks during the transition until a friend and I switched skimmers. He had an ATB Elegance 200 Pro on a 60g system that only skimming intermittently. Since the beginning of August, I've been running just one ATB Elegance 200 Pro (rated to 300g-ish). I've been planning on running two skimmers the whole time since I have a big footprint in the under-tank sump but I don't have a lot of headroom (31"). I was also limited on what I could fit through the gap between the top of my sump and the top of the stand: at best, I could have gotten a 10.5" diameter skimmer in there. I started looking at needlewheels since I had previously ran them with success -- in particular Reef Octopus, Reef Dynamic, Skimz and Vertex all seemed nice. Then I started looking at other options besides needlewheels. I came across some threads about "Lifereef" skimmers and all of the users were raving about them.
After reading Lifereef's website, multiple threads, watching youtube videos and exchanging PMs with a local guy running one, I called them up. Jeff, the owner who also happens to be the manufacturer and customer and tech support (yep, one man shop!), and I spoke for over an hour about his design and my system. I ended up ordering the SVS3-30 model with a slightly modified cup to ensure I have enough room to remove it. He literally hung up the phone and started making my modified skimmer cup -- it ships tomorrow!
The plan is to run the Lifereef and the ATB side-by-side. I should get a good feel for which one performs best. Assuming they're equal, I'll keep running both and run the ATB "wet" (since that's really what it does best anyway) and the Lifereef however it wants to run. If the ATB is clearly slouching in comparison to the Lifereef, I'll add another Lifereef and remove the ATB. I have a Waveline DC12000 on hand that I think would work perfectly as a feed for 2 SVS3-30s. We'll see.
I'm still not sure which pump I'll put on the single Lifereef when it comes in. I have several back up pumps, pumps from old builds, etc. The potential list includes: the previously mentioned Waveline DC12000, a Reef Octopus DC5500, or an Eheim 1262. A friend has a Laguna 1350 that he said I could try out too. There might be a little trial-and-error but really, any pump that pushes between 900-1200 gph should be sufficient. That also happens to match the flow though that portion of the sump.
Noise always plays a big factor in my decision, which is why I liked this option. According to Jeff and owners of his skimmers, they're as silent as the pump you put on them. I like that. I know my Reef Octo DC5500 is silent. I know the Waveline DC12000 is silent. So this should be a good match. I'm looking forward to the comparison and I'll be sure to share my results.