I have a "performance guide" on my website that can serve as reference..
Basically,
you can run about 400cfm through 2 hoses up to 400 feet each,
or 350cfm through about 500 feet of 2" vac hose.
The question, is how many tools do you want to run,
How many CFM do they require, and what distances will be most convenient.
Your jobsite, available tools, and team strength ON the SITE
is where you calculate your required performance. Eh ?
400cfm still allows you to reduce the engine-speed for quieter running,
without lugging the engine below its HP-curve.
350cfm has power to spare,
500cfm would waste gasoline, and drag it's feet at high-lift.
or run 4 tools at shorter distances.. 4 guys with 12" surface cleaners
could clean a bakery or locker rooms wicked-fast !