Yeah definitely Andy will be able to guide you with the setup.......The riser is actually the tower that the beckett sits in and is connected to the skimmer housing.....If you look at the MRC skimmer you'll see 2 smaller tubes and there is a black foaming head inside these risers......This is where your beckett is housed and where the water is forced through these to create your bubbles.....Along with the riser tubes are air flow valves so you can fine tune your bubble size to skim dry or wet........
The main riser is your main tube coming up from the skimmer body.....These to can have section added on to increase the skimming capacity of the skimmer.....If you check out their site, and scroll through it will explain how easy it is to move the skimmer from 1 size tank to another with simple riser upgrades.....He can and will custom make a skimmer to fit your application if that's what you'd choose......Again he'll be able to answer all your questions and guide you to a "T"......