the nylon pipe i use is the 12mm stuff, which is the standard air line size for trucks it seems, i run my compressor at 150 psi, and draw off about 8cfm max, but i only have about 40 feet of the pipe, plus a pull out hose reel about 20 meters long,
but for your length of pipe, i would deffo think about going up a few sizes in the pipe,
i can't recall what the nylon pipe cost me, but i am a professional tight arse, so i wouldent have bought it if i thought it was too expensive, fittings were cheap too,