Seafarer

Just exactly how does the Glendenning sync system work?
What to look for and repair if it's not working correctly?

I am trying to find out the difference in fuel burn between a 43C Sportfish and a 45C and 46C Sportfish with the same engines in each vessel.
This vessel will be used as a Charter fishing vessel.
So I am looking to find the best fuel efficiently possible.
Can anyone help me with this please?