I tried searching, nothing popped up with specific answer. Disclaimer, Pretty new to car audio

So i just bought 2 RF p3d4 and a RF Prime 1200.1D. The subs are wired down to 1 ohm (amp stable at 1 ohm at 1200 watts RMS) the amp suggest 4 awg power and ground, and despite what specs sayin that it accepts 1/0 gauge wire, it looks, and other people say, its already hard enough to fit 4 awg. Whats kinda the paradox is that at 1200 watt 1 ohm, and a power wire running about 13 ft (ford focus '09) the amp should be pulling well over 120 ampere. Somewhere around 170 if im actually pluggin in the right equation. Isnt 4 awg really only do about 1000 watts and /or 120 ampere?

So i guess my question is, at 1200 watt rms, would i be starving/clipping my amp with 4 awg wire? Keep in mind though, i will buy RF 4 awg OFC wiring, so i know the ofc will make it more efficient. Also, what kind of inline fuse would i want to put in? The RF 4 awg power kit comes with a 100a fuse, is that good enough to protect amp?

Thanks !!