1 liter means a wide pot I assume, which is optimal for efficiency.
If I can find an excuse to skip, I mean, avoid, I mean, with great regret put off, work, I mean, try to sacrifice all for science, I will test a standard 6 jet penny stove in a standard wind screen on 1 liter and see what it starts out as re fuel consumption, then maybe test a more optimized version. The 6 jet is fast, that's for sure, it burns really hot because the jets hit the sides of the can to heat the fuel.
The cones will be a bit more efficient, but not by a huge margin, it depends on how many days trip you are talking about.
Because making a cone takes a while, I won't do that for now, but it is an interesting question.
If I were to guess, I'd guess about 22.5 ml will boil 1 liter water with a wide pot, that's a guess though, the burn characteristics of alcohol stoves varies depending on many factors, including how much fuel they contain for the burn, so it's almost impossible to actually know without trying.
I believe with alcohol stoves, the idea is: fast, efficient, pick one. cones will have different requirements for stoves since they contain the heat more which changes the stoves performance significantly.
However, for 1 to 2 days trips, put your canister and your stove on a scale, and I do not believe it's possible to carry more weight using alcohol because with alcohol you can carry the exact amount of fuel you need in a very light bottle, and the stove itself weighs virtually nothing.
But the joy of alcohol is in the silence, the absolute silence, the total non machine sound, nature is there, you are there, and there's this thing on the ground that you really have a hard time believing is actually doing anything at all in terms of cooking because it's not roaring and sputtering, and the only way you really know it's on is by putting your hand over it. Some alcohol stoves make tiny little boiling sounds and sometimes faint little sputters but you'd be very hard pressed to hear those sounds with any ambient noise around you. A canister stove to me is like bringing my house stove with me, attached to the gas pipeline. And I used to really like xgk and whisperlight cooking, but the first time I did alcohol, I was sold, that silence is priceless.
Re simmer times, a stove like the penny simmers phenomenally well, I doubt anything gas/liquid powered comes even remotely close to the simmering performance, I could not believe it the first time I tested it, I had to keep checking to convince myself the flame was still going. If you simmer, I don't believe anything can be compared to an alcohol stove, then it's a no brainer.