2016 AF811SB..What is 60 amp circuit breaker under step for?

There is normally a large rated circuit breaker to protect the wiring in the rig.
Your 800 watt inverter, is it peak or continuous rated?
How much load are you going to draw from it?
#8 would be a little light for full 800 watts. You could increase size of wire to 60 amp and then tap there. Your jacks could be source, but they may have fuse or circuit breaker near the battery as well. This would need larger wire as well.