I initially installed a 4 channel amp using an 8ga kit. it didnt take long before i decided to add a sub and monoblock amp. i ended up removing the 8ga and running a 4ga NXG kit from Sonic.
It will be much easier to manage a single 4 ga run than 2 8s. Just make sure you fuse properly.
As far as wiring, take a look at the PAC FRD24 harness.
I took your advise and ordered the ZCK44 4-Gauge kit today, but I wanted to clarify the fuse situation. The ZCK44 comes with a 100a fuse included for the inline holder. if the ZX700.5 takes three 30a fuses and the CX300.4 takes one 60a, what size fuse should I use? Kicker only makes 60a, 80a, 100a, and 200a fuses, should I go with a offbrand 150a fuse maybe? btw, thanks for the info!