Working on the principle of the fuse protecting the wiring
you rating sounds reasonable, you have rated the main fuse to be higher than the max. load and less than the wiring / hardware
As soon as the downstream wiring and / or bus is rated lower than 350 amps, additional protection is required "downstream".
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence