I use 3/4" camlocks on my portable fillrite pump. But 2" on my IBC tote since it has a big drain on it and I picked up a 2" fuel hose for free. Adapters are cheap. This "hobby" depends more on adapting what you have than designing from scratch. Personally, I would wait til the end for fittings. See what centrifuge, pump, and skid mount we can get our hands on first.