8 gauge or 4 gauge wire

[Drew01SS]

I want to power a 150 watt amp, a nitrous bottle heater, nitrous bottle opener, and a nitrous system consisting of a n20 purge solenoid, relay for n20 and fuel solenoid, relay for bottle heater, relay for bottle opener, and power for a window switch off of one distribution block. I will power the n20 and fuel solenoid with a different power source. The amp has a 25 fuse in it, the bottle heater is protected by a 30 fuse, the purge solenoid uses about 10 amps, (3) relay coils at ? amps (less than five), a window switch at ? (less than 5) and a bottle opener at 20 amps. There's no way I will be using all loads at the same time, but I want to do it right the first time. Should I be using 8 gauge or 4 gauge to the distribution block?

[KMdef9]

4 will be good. Good for the future as well.

[Joe00SS]

Do it right the first time and go 4