Bean,
I was never a 'bubble plate' guy or not one. Maybe some people got the wrong idea when I commented about how a year or so ago the 'fad' seemed to try to modify every skimmer out there with a bubble plate, which I was trying to point out might actually work against you depending on the situation. If you have a skimmer body that is too narrow, the bubble plate is more like a wide hose... and it doesnt diffuse turbulence so well... kinda like the bubble plates on an ATI. You might be better off just aiming the outlet of the pump down into the skimmer, or if the body of the skimmer is large enough in diameter, swirl it. I was never against bubble plates... I just dont think they get implimented very well. Its not just something you can slap in and then make a guess as to how many holes or what diameter they should be.
Over the past year, I have figured out 3-4 ways that you can actually pack a small bubble plate into a taller, narrow skimmer. A spherical bubble diffuser rather than a plate. A taller bubble diffuser chamber with a water bleed at the bottom, etc. So there are ways... But still, I dont think I could give up preferring a taller skimmer all together... thats why I could never bite the bullet and buy a short & fat bubbleplate style. I have figured out how to convert any traditional needlewheel into a 'bubbleplate' skimmer though... so one could convert their deltec AP into a BK or ATB... just 2 parts needed (somewhat fancy parts, but still reversable).
Honestly, when you start feeding an eheim 1262 threadwheel anything over about 1600lph of air, the output turns into shaving cream... so its not like you even need a plate on a taller skimmer when you force feed it.
Always been a tall skinny guy though... always. I could never give up the height. The current skimmer is just 'enough' for what I have now at 30" tall, but my intention was to run a 5' skimmer all along. I can see how the turbulence reduction can make up for being shorter, as long as its done right that is. Look at the 22" tall ATB cone. Then look at a H&S A200 1260 that is just under 30" tall. They really very similar stats-wise. Same pump, same distance from the pump outlet to the top of the skimmer. But the H&S is more turbulent, while the ATB uses that plate. So while the H&S bubbles might have the same distance to go, the ATB seems to do it under better circumstances. Im sure that shaking off some turbulence can in effect add to the height of the 22" ATB, which is really the same if not better than as the 30" H&S then in the end. Otherwise, this is the design I was considering:
4' tall AND a bubble plate.
Try the eheim Bean. Just buy the 1262 pump, then plumb it w/o venturi of course (force feed), and get the needlewheel impeller from Euroreef, and cut the pins off... drill holes like the ATI, and add 4 layers of PF4... it will rock. Much quieter than that OR. Heck, maybe the stock ER needlewheel is enough for your skimmer from what it sounds like. Cooler tool. But yeah... I have never gone over 28 scfh (about 800lph) with the OR 3700s. I would say its a good match for a tall skimmer if you didnt force feed... but thats not the case. I never did try meshing mine though... could help. Meshing seems to help the maximum air handling of any pump when force fed. I swear I could get that eheim up to 3000 or 4000lph.
Not knocking Alita one bit, but the GAST ones seem to be the same thing (some of them at least). Ever messed with them? I see them showing up on Ebay all the time for cheap (some smaller/more convenient sizes as well). I wonder if maybe they arent the OEM for Alita?