Over the past 2 years I've added less water to Costco Argentia wine kits. I use a 19 litre carboy instead of 23 litre carboy and the difference is amazing.
You get 50 bottles (25 X 2) rather than 60 bottles but 10 fewer bottles is a small sacrifice for the quality improvement. So far, I've experimented with the Merlot, Pinot Noir, White Zinfandel, Chardonnay and Shiraz. At first I made 23 litre and 19 litre batches of each to compare.
I'll never go back to 23 litres.
One more trick. The White Zinfandel is a pretty good wine that comes with a liquid sweetener made of wine sugar that you're to add at the end. I don't like my wine that sweet so I stored up a bunch of the sugar packets.
I now add the packet at the beginning with the juice to up the sugar and therefore the alcohol level. It's not a huge increase in alcohol but I can tell the difference in side by side taste tests and prefer it.
The best Argentia wines to my taste hands down are the Pinot Noir and the Chardonnay. Wine snobs I know who always shunned homemade wines tell me — it's not horrible. One even said, thinking it was an insult, my wine was no better than McManis. Well in Canada (Ontario) McManis costs $20 (Cdn) a bottle. My wine costs $2.