500 gallons is still pretty small scale. 4.5 tonnes of grapes
most little wineries would ferment reds in half tonne picking bins and do punch downs manually. its only ten bins to punch down. and at this size fermenter heat build up is not a problem.
since you need a forklift for handleing these bins , you don't need a must pump. a used forklift with a bin tipper is cheaper than a must pump , and you can rent these for even less for the harvest season . you can use the bin tipper for crush and press filling
a half tonne capacity press would be fine and a crusher stemmer that can do 2-3 tonnes an hour would be fine. my home one does 1 tonne per hour , if your harvest and crush is spread over a couple days this would be fine but a 3 tonne per hour would be better.
flex tank cubes could be used for fermenting whites or doing mlf in on reds. a vacuum pump or a forklift can be used for racking ( a small 1 tonne forklift is a winemakers best friend in a small scale winery)
mixing nutrients can be done on a by the bin basis , your home blender is perfect for this , and a half gallon starter culture per fermenting bin is the way to go for your yeast.
and if you have lots of hands and some time you can use smaller gear, we make 300 gallons per year with a 1 tonne an hour crusher stemmer , an 80 litre bladder press , 55 gallon brute bins and 4 small tanks and a slew of demijohns and carboys .
going to another 200 gallons would not be a big step up, just need more time and storage capacity. ie crush would be two days instead of 1 and press would also be two days with 4 people working . no fork lift , no must pump. just sweat equity .
we bottle the 300 gallons in a day with 2 enolmatics , 2 Italian floor corkers and 6 people , two on enolmatics , 2 on corkers , 2 feeding empties in and taking full cases away , rotating positions every hour.