Know a guy who ran his on meths and said it was better than you would get with coal or gas. pics here, here and a nice meths tank here
What he said on TT
"HI
You wont get the pressure with gas, but a good six wick meths burner with half inch wick pipes will pile steam on faster than you will need. Your about to be bombarded with tales of safety surrounding methsburners and horror stories of burnt out engines. Well yes it can happen and im sure does happen with meths, but with care and a well for the meths to feed from the problme is almost zero.
I make better steam with the meths burners than ever I could trying to burn coal in the Minnie. The firebox is just that bit too small for it to be succesful. Even the 3.5 inch gauge Tich loco has a larger grate area and thast saying something."
"The burner was in truth cobbled together to solve a probelm and answer the question "would meths fire a Minnie?" I had the grand idea of making a nice well made one later on but never got round to it.
The wick tubes are half inch diameter about 3/4 long. With the engine running slow or fast the fire from the burners fills the box but does not give any unburnt meth smell at the top of the chimney, a good sign.
The meth feed can either be held in a tank that is level with the top of the wick tubes so the wicks cant over flow, or as I did use a globe valve to regulate the flow. Either works well."