I have just completed exactly that issue for a European spec Oyster
55 as a live aboard stateside.
First easy fix. The Victron 3600 watt auto voltage input isolation transformer works extremely well. Apply 110 volt and get 230. Apply 208 volt you get 208, apply 240 volt you get 240 volt.
Ensures the neutral and hot are right and removes any galvanic path to shore.
In my case I wanted to be able to run large 50hz only loads on shore power if desired. So two modes of operating.
Transformer to 100 amp at 30v charger
then make 230 volt 50 cycle power with a victron quattro 8kva inverter.
Other mode, feed output of transformer directly to inverter, limit shore power from transformer to 16 amps, inverter can add as much as 8kva so 12kva total if needed. Has 200 amp at 30v charger built in.
I normally run in the first mode...
For 110v equipment
I have a 1200 watt inverter only which powers a parallel set of outlets to the 230v outlets.
The nice part of the quattro inverter is built in dual inputs so if I turn on the generator it drops shore power and shifts to 50hz. With the 6kva generator I can source 150 amps at 30v for charging
and can provide as much as 14kva to house loads for 30min or more.
Currently I have about 440 ah at 24 volts which is working very well