I doubled mine quite easily-I added a second standard Westy tank (from a
totalled Westy) under the other side if the van. The bolt holes are there! I
left the kitchen hooked up as it was,and hooked the Propex up to the second
tank. Last winter I camped out in the northwest and the Propex would run
about a week and a half on a tankful. A cheap and aesthetically pleasing
method if you can find an extra tank as cheap as I did($60).
   My opinion of the Propex: A great,super-compact unit that is very
fuel-thrifty. Works wonderfully until temps drop into the single digits or
below 0. At those low temps it will run constantly,and only achieve an
interior temp of 45 f. My next step is to insulate more/better,so that 65 is
attainable all the time. And my dog loves it- nice warm floor-bed to sleep
on,what more could a dog want?

Karl
'87 Westy Syncro 'OTTO'