Plumbing into heater supply circuit
 

I have two questions about plumbing into the heater supply circuit on my 6.9L navistar diesel.
First, I would like to install a tank type block heater to prewarm the engine in the winter to save cranking stress on the starter-battery system. The heater supply circuit comes out about 1/3 back below the valve covers on the passenger side and the other end goes to the water pump. If I plumb in the tank heater there it seems that I will be warming only 1/4 of the engine. Is there a better place to plumb in the tank heater?
Second, I plan to run fuel line and fuel tank heater lines to preheat my biodiesel in the cool weather. Will the heater circuit supply enough hot coolant for both the cab heater and the fuel heaters? Is there a better place to connect to?
I have encountered an annoying problem with the biodiesel I make from waste vegetable oil. There is apparently enough animal fat in the used oil such that as the temperatures drop below freezing the methyl stearates precipitate out and plug the filters. Blending with kerocene doesn't solve this problem. If I warm the biodiesel back up to 35-40 F the precipitate disappears. The 3/27 test indicates 90+ coversion to biodiesel.
Has anyone else encountered this problem and is there a better solutions than heating the tank.

Cant help you with the first part

Which veggie do you think you are starting with? Mixed? Youll need to contact Fabman, he has a line on a product that will drop the gelling point 30 degrees. You can put the completed process through vacuum and remove the remaining particulates easy enouph. Fabman's process removes the methanol from the bio and any remaining soaps and glycering immeadiatly falls to bottom. 1 micron filter and then you should be as near as 100. But how much more work do you want to put into? Most all the bio fuel is gelling at 30-40 mark depending on Soy, corn, and canola oils.