Stoves systems used
The Trangia 25-1 which uses Methylated Spirits is a very popular stove. All pots, windshield and burner fit together very nicely. The pots are 1.75 liter and 1.5 liter capacity. System weight of 865g without fuel bottle.
MSR Whisperlite which uses Shellite and is also a very popular stove especially for cold climates. With this stove I used the MSR Alpine 2 Stainless Steel pot set, this pot set is designed to fit the stove inside. The pots are 2.0 liter and 1.5 liter capacity. Complete system including pot grabber and windshield has a weight of 1090g including fuel bottle.
Kovea Supalite which uses Propane/iso-butane gas mixtures, these lightweight gas stoves are becoming very popular. With this stove system I used two cheap Billy’s, 1.25 liter and 1,5 liter capacity, all contained in a mesh bag. System weight including pot gripper and windshield has a weight of 424g without fuel container. (This system is what I actually use outside winter when two pots are required).

The three stove systems (note the Trangia pictured is a 27-1)

Kovea/billy pot system

MSR Whisperlite stove/pot system

Trangia stove/pot system
Estimated daily fuel use
Daily fuel used was determined by using figures from Roger Caffin’s http://www.bushwalking.org.au/FAQ/FAQ_E ... sage,these figures are for fuel used per day for two people.
These figures have been determined by Roger notes of his fuel usage in the field and other walkers reports over many years and the figures given here are specified as reasonably conservative.
Methylated Spirits 80-100g (used 95g in calculations)
Shellite 50-60g (used 55g in calculations)
Gas 30g (used 30g in calculations)
Note: in cold weather fuel usage can be higher and if melting snow it will be higher again.
In all of the calculations I used an amount of fuel that was rounded off to an amount just above the fuel required. Eg; for three days with the Trangia 285grams of Methylated Spirits was required, I rounded this off to 300g grams of fuel.
Graph 1, 3 day comparison.

Trangia 25-1 system, with one 500 ml fuel bottle (35g) no fuel weight of 900 g, all up weight with 300 g fuel 1200g
Whisperlite system, the fuel bottle was filled with 250 ml (185g) of Shellite for a no fuel weight of 1264g and all up weight of 1449g.
For the Kovea system I used one 100g canister and one 230 g canister, I did not put the 450 g canister figures in as It is not practical to use this canister for a three day walk.
System with 1 x 100g canisters 512g, all up weight with fuel 612g.
System with 1 x 230g canisters 558g, all up weight with fuel 788g.
Graph 2, 7 day comparison

Trangia 25-1 system, with 7 days fuel 850 mls of fuel was required for the 7 days calculations I started with a full 1 liter bottle, no fuel weight of 913 g, all up start weight with 800g fuel 1713g
Whisperlite system, with 7 day fuel, 520 mls was required in the calculations, I started with 650 mls of Shellite,.
System weight with no fuel weight of 1264g and all up start weight of 1754g.
For the Kovea system I did calculations with two 100g canisters, three 100g canisters one 230 g canister, and one 450 g canister
System with 2 x 100g canisters 600g, all up weight with fuel 800g, This is 10 grams short of the required fuel but was put in to show that if careful it can be done.
System with 3 x 100g canisters, no fuel weight 688g and all up start weight with fuel 988g
System with 1 x 230g canisters 558g, all up start weight with fuel 788g.
System with 450g canister 643g, all up start weight with fuel 1092g
Graph 3, 15 day comparison

Trangia 25-1 stove system with 2 x 1liter plastic Methylated Spirits bottles at 48 grams per bottle filled with 1800 mls at start.
System weight without fuel, 961g, all up start weight with fuel 2401g
Whisperlite stove system, 1115 mls was required in the calculations, I started with 1200 mls of Shellite.
System weight without fuel 1254g, all up start weight with fuel 2142g
For the Kovea system I used 5 x 100g canisters, two 230 g canister, and one 450 g canister
System weight with 5 x 100g canisters 864 g, all up start weight with fuel 1364g
System with 2 x 230g canisters 691 g, all up start weight with fuel 1151g
System with 1 x 450 g canister, no fuel 642g, all up start weight 1092g.
Conclusion.
It is obvious that the Kovea gas stove system comes out on top in all of the calculations, the outer advantages of gas stoves is the fine control of the flame which is not available with the Whiserlite and to a lesser extent the Trangia but as to which stove system you prefer you can make your own conclusions, I hope these graphs will help.
Tony