Sounds about right to me. I use 3, (-100), for the engine though. I have a wash down that takes about 3/4 gallon by itself. I bypass the heater too. I use -60 for all plumbing. I don't seem to need that much in the forward tank as you use though. I make sure all tanks are empty before starting to winterize. I use the center tank to winterize all the fixtures as it it close to the manifold.

I usually poor a little down the sink drains and the fridge drain. My boat has AC also, so I pump some through that as well. 

Don't forget to drain the strainer at the engine water intake, and AC intake (again, if you have AC). 

Beautiful photos Rich. I was going to submit a photo of us sailing on Christmas day here in sunny Punta Gorda, Florida, but after seeing your artwork I don't think so. I better get Caprise winterized by taking off the Bimini top then go sailing for the rest of the day.

I do not put any antifreeze in my water storage tanks.  I run the fresh water pump with kitchen taps open until each tank is basically empty then bypass the water heater - just let HX drain into bilge then drain.  Remove hose after tank valves and T and run water pump to run pink antifreeze to all taps (one at a time).  Never had an issue in 7 years up here in the Great White North :-) .     M25 engine (raw water filter, pump, heat exchanger & water muffler) takes about 1.5 US gal.  I pump the toilet dry and put in a cup of pink antifreeze.   None in bilge - try to keep it as dry as possible although some water comes in via the mast when up for the winter.  Never been more that 1 or 2" - frozen solid but no problems with bilge pumps (just never turn them on when frozen).
I flush the fresh water tanks (via taps) with tap water three times in the spring.
Gary Steeves  Aluna MK1 Hull #405  
All winterized and tarps on - now waiting for skiing season :-)

Doesn't a lot of the vodka evaporate over 6 months on the hard?

I follow MaineSail's excellent advice on winterizing - ​https://marinehowto.com/freshwater-system-winterizing/
He makes some good points on why not to use vodka for winterizing, the most important is the additional cost and evaporation. 

I use about seven gallons of pure propylene glycol for the head/holding tank (2 gal) fresh-water system (3 gal) and the AC (2 gal).  I open the connection for each throughhull and put the inlet tube into a gallons of pink stuff, or a bucket of it.  That way, it runs all through the systems, including into the rim of the toilet.  I  pump all fresh water out the rear shower, then open the connection from the water tanks prior to the fresh water manifold and let the remaining water drain into the bilge.  I never put pink stuff into the tank itself as it's dry.  If you have a difficult time removing any hose, heat it for a minute with a hair dryer and it comes right off. 

I leave all through-hulls open on the cradle so that the system continues to drain and can't accumulate in the seacock. I stuff a bit of plastic scrubbing pad up from the outside to prevent any bees from making a home in the tubing.

Don't buy any pink stuff that is not 100% propylene glycol.  The cheaper stuff is flammable, poisonous, and can cause corrosion in non-noble metals in your pump.  It's not worth the $1.50 savings per gallon.  If it says poison or flammable on the bottle, put it back on the shelf.

One good (cheap) tool is the sight refractometer.  For less than $20 you can make sure that the "running pink" at the faucet really is the same concentration as the stuff in the bottle.  I check each faucet with a drop on the refractometer to see it reads the same as the pure stuff from the bottle. Any dilution is a potential freeze and damage to your non-flexible parts (faucets, pumps, fittings - the expensive stuff).  Don't forget to run some through all your bilge pumps and leave some in the head and bilge.  If you have ever replaced a water pump (or worse, a holding tank hose!) you will not think about 'saving money' for a good, thoughrough winterizing.

Thanks for that, John!  I had not read MaineSail's post and you brought up some points I'd not thought of (bilge hoses above the backflow preventer).