Coming from a mead background, I'm not given to much precision with
quantity-of-sulfites. That said, I'm attempting my first grape wine --
the Island Mist Blackberry Cabernet kit. Given that the guys who
made the kit know exactly what's going into it, can I assume
the amount of sorbate-and-sulfite included is sufficient to
protect it for a year or two?

What if I brew this 6 gallon kit as a 5 gallon to get a little
extra oomph out of it? Will I likely need to de-acidify it later?

Thanks!
WB