The kits we are discussing have an initial volume of 6 US gallons / 23 liters. The final result will be less due to sediment and racking losses.
The kits I'm familiar with come in 3 sizes: 1 gallon, 3 gallon, and 6 gallon. The 1 and 6 are typically table wines, while the 3 gallons are specialty wines like dessert wines. Fruit concentrates may be designed to reconstitute to other sizes.
I made the WE Reserve Australian Chardonnay a year ago, it came out very good.
I'm looking to make another white -- was hoping to get fresh Verdicchio, but that may not work out. I'm considering the FWK Chardonnay.