I used to wire aircraft.
If you really want a 'one size fits all' then I'd go 16 g but always protect based on wire size and not current draw.
OEM's usually like color for easy foolproof assembly and use the smallest size needed to save $$'s.
Aviation likes to wire stamp to identify each wire.
A tractor cares less about weight and U probably don't want to buy 12 different spools of color wire nor different sizes.
Go the good old way, all white #16 and use masking tape to identify both ends of your wire.
Once re wired use tie wraps to bundle your harness and make sure it doesn't chafe anywhere, use whatever means to isolate wires from abrasion on tractor parts.(stand offs, tie wraps, grommets etc)
10 amp fuse or breaker would protect from fire hazards on 16 g wire.
Fuse or breaker is not there to protect the instruments or other device its job is fire protection!