Yeah, seconding the comments to reassess some of those load currents before investing in wire.
- you only require one 30 A fuse in the battery run. Omit the fuse to the right of the battery switch
- I would upsize the wires between the battery and the bussbars, and select a battery fuse type that you could later upsize... to permit
- why not install a small DC breaker panel instead of fuses
- add a circuit for your VHF radio
. How 'bout a stereo
- I like to add a cigarette-lighter-type 12v socket or two on a 10A breaker for stuff like a 12v cooler, fans, spotlight, trouble-light, computer charger
, small (75w) plug-in type AC inverter
, 12v to USB for phone charging
, etc etc.
If you could update your drawing with rough estimates of the wire runs, it would be easier to double-check your wire gauge choices.