There is a deck pump out port and the PO showed me a piece of short hose that's used for pumping out. I'm going off of memory.
You shouldn't need use any hose to pump out, just a fitting that threads into the deck pumpout fitting to connect the dock pumpout hose.
I've seen diagrams online of macerators between the head and holding tank and also between the tank and pump out. Which setup is best practice?
There should never be a macerator pump between any tank and the deck pumpout fitting...the dock pump sucks the waste out of the tank. A macerator pump in that line would interfere with pumpout. However, some owners find that the self contained tank can't hold enough for the amount of time they want to go between pumpouts, so they install another remote holding tank and reroute the pumpout line to it using a macerator pump to transfer the waste. That would be the only use for a macerator pump between any toilet and holding tank. Any maceator pump in the TANK discharge line that connects to a thru-hull would be used to dump the tank which is illegal in all the Great Lakes, in fact in ALL U.S. waters. To dump a tank legally you must be in open ocean at least 3 miles from the nearest point on the whole US coastline.
It's sounding more and more that what you have started out as a portable portapotty that the PO jury rigged into one that can be pumped out or dumped without the slightest idea of how it should be done. I'll know for certain when I see your photos.
I'm guessing that this is your first boat big enough to have a sanitation system...in which case I think you'll find my book (see link in my signature below) very useful. The title is a bit misleading...although it does deal with every source of odor on a boat and how to cure, or better yet, PREVENT 'em, it's actually a comprehensive "marine toilets and sanitation systems 101" manual that explains the laws, describes all the types of systems and will help you learn how to operate and maintain your system to prevent 99% of problems instead of having to cure 'em. 'Cuz you get to do any preventive maintenance on your terms when it's convenient...the need to cure a problem never happens when it is!
--Peggie