You could approach this methodically.
- what does the windlass manufacturer recommend for circuit breaker rating?
- what gauge wire, and how long (round trip)?
You should observe the windlass maker's recommendation,
and protect the wire.
To protect the wire you determine the max current rating based on the ampacity and the ambient temperature, with also a consideration for whether the wire is in a bundle or "free air." If your installation was designed for a max 3% drop, you probably have plenty of margin in wire protection if you size the breaker for the windlass.
(I'm surprised you have a 90A breaker, my Lewmar Pro Series 1000 (1000 lb. pull rated) has a breaker specification of 70A.)