You really don't want to be using a potable water can as a condenser can for a Vickers - there's enough contamination inside the barrel water jacket to make the tea taste disgusting. (So I'm told, at least.)
A MMG is not a suitable tea-making appliance - using a mess tin and plastic explosive[1] is faster and a lot quieter.
Chris. (Has only ever used hexi blocks or a Primus.)
[1] strip the paper wrapping off, roll it out into a pencil-thick sausage and arrange in a spiral on a metal sheet with a bit projecting over the edge. Light the end and follow the flame with the water-filled mess tin. Silent and it even works in the jungle when everything is soaking wet.