2014 400 Cuddy Holding Tank Operation

Hi

We just recently picked up a used 2014 400 cuddy and need some help on understanding the plumbing. I have read the user manual but it does not specifically answer my questions.
1) Is there a macerator between the head and the holding tank? Or is maceration only done when pumping overboard from holding tank?
2) If 3nm offshore and the Y diverter is in overboard position and seacock/thru hull open, does waste flow straight overboard without maceration?
3) There is a Y diverter valve after head before the holding tank for overboard or holding tank selection. If I am 3nm offshore and I am going to pump from holding tank to overboard, does the Y valve between head and holding tank need to be in overboard position? Or does the holding tank have a separate line to a seacock/thru hull and I just need to make sure that is open?
4) After emptying holding tank and running internal water spray down is there any else I should do to treat holding tank before reusing?
5) I read in the manual that there is another Y value under the sink in the head. What is that used for if I have a Y valve right before the holding tank to select overboard or holding tank?

Thanks
Jason