Electric plan for 3 banks with Battery monitor

[Sea Angel1]

I have 2 active battery banks - 12 V each), 1 for motor (55 HP) start (100 Ah) and 1 for service (2 batteries in parallel, total 200 Ah). 1 spare battery (100 Ah). This one can be switched separetely on to each bank.
Charging: alternator 115 A through a 3 pole diode bridge - master volt 1603
for 3 banks (motor - service - spare)

PV max 300W, in practice appr. 12 and 18 Amp between 9 am and 5 pm
Wind Gen: strongly varying - in general up to 0 -15 Amp (4 Bft).
Controller output only for 2 banks. this is not sufficient, because spare bank is not being charged. Manual switching required to keep fully charged.
Location: east Med
experience: sufficient charging power in summer.

I want to improve the system and install a Victron BMV battery monitor on the service bank.
A proposal how to improve this system, including the wiring up of the shunt for the motor and spare battery would be much appreciated. A schematic would work out ideally.