a good friend who works at sears and handles all their return merchandise states natural gas grills are often returned because users report they dont get as hot as propane. propane definetely has more BTUs than natural gas.
you might be disappointed in the conversion. I didnt convert mine for this reason.....
i solved the empty tank issue by watching for people getting rid of grill tanks. a few bucks here and there.
i quit finally after getting too many tanks for free / near free. have
6 or 8.
I take them in once a year and get all filled.never run out. they also run a propane bullet heater, i use once in a great while, also good for emergencies...
exchanging costs more than filling at a station with a propane fill tank, convenience store exchange twiice fill cost.
i do exchange once old tanks with obsolete valves. the exchange places install new valves to send the tank out, and i benefit.
if a tank starts to rust or look shabby i exchange it, not worth the effort painting. let them do it,
well thats my solution to running out of propane, i store extra tanks in my shed far away from house, and its always well ventilated, just n case of a leak.