I think mostly it comes down to what you're cooking and how you're cooking it.

Those propane "burn time" figures I was using DID seem a little "conservative" to me but they came straight from the manufacturer of those cylinders.  Re: using single vs. two-burner stoves, well... the way I look at it, using two burners uses propane twice as fast BUT requires approximately half the burn time.  In other words, feeding four people gets done in half-an-hour vs. an hour but, ultimately, uses about the same amount of fuel.

But I'm no cook, so what do I know?  I'm just doing the math.  There could easily be other considerations I'm simply not thinking of regarding fuel consumption.

However, we arrived at the number, it seems like both PD and I are saying you'd do well to pack 4 cylinders... and maybe toss in a 5th if you want to be extra safe.

Jimbo   8-)