Away for a couple of days, and look at the traffic!
I can only report what I use. Cooking for TWO people in summer I use 30 g per day. In winter without melting snow this goes up to about 40 g per day for TWO people. Melting snow adds a bit of course, but I can't give exact figures, because sometimes I get sneaky and burrow down to a creek. It's worth the effort.
How do I get such good figures? Three things: lid on pot, windscreen around pot, and I run the stove on a medium to low setting. I am sure everyone knows about the first two factors. The windscreen actually does TWO things. It blocks the wind, which makes the stove a lot more efficient. But it also forces the hot air closer to the pot, which helps heat transfer.
I cannot emphasise enough that the third one is equally as effective. By dropping down from a flat out burn to a more gentle burn, I halve the amount of fuel used. When the stove is running flat out there is a huge amount of heat wasted up the side of the pot. OK, it heats the snow cave or tent ...
Manufacturers' claims about boil times are usually unverifiable (you can think of one notorious example quite easily!), but also totally pointless. Flames to the roof ...
But there is another factor coming in here as well. I was looking at the amount of water Ryan J was talking about per day. I forget the exact amount, but it seemed a huge amount to me. In the snow I would be using less than 3 litres per day for everything. The amount of water to be used/melted is therefore something to consider carefully. But Ryan will have to decide this one himself.
A foam pad (or lighter equivalent) under the stove AND canister is needed, but gee that could be light. 5 mm EVA 30 foam would be gallons. A bit of an old foam pad ...
What all this means is that if RJ started out with some water in his pack for the first day (and that water is NOT counted in the base weight!) then he really only needs to plan for two days of water. Now a 170 g Powermax canister would give him 85 g of fuel per day. I still say that is enough. I still say he should have some left over when he gets home. But, hmmv.