There should be a Manual J calculator online for $50.
"The energy content of shelled corn is not a constant value because of biological variability and management factors. Generally, the energy content of corn is in the range of 8,000 to 8,500 BTUs per pound of dry matter."
so corn that is not bone dry will give you less BTU than a scale will lead you to believe. By comparison, propane is ~22K BTU/lb.
Other things being equal, if propane is available to you, on a per pound basis, the corn/propane fuel choice decision would be a tossup if the propane costs 22/8 x what the corn costs.
should tell you how warm or cold your area gets. Getting from here to your answers will take a little work.
BTW, if there is a Wikihow for doing your own medical treatment, surgery, etc., the doctors would be out of business. . .