I have read and gained knowledge about diesel engines by reading this forum and xulfiqar indepth knowledege. carefully i can say the pump needs fine tuning. 10 heaters and engine refuse to roar is not problem with heater (glow plugs), pump / injector need thorough diagnosis.
a desi totka shared by an engineer working up north on KKH - wrap the fuel tank engine feed line section with seat warmer (pillow cover sort of thing) plug it to lighter 5 minutes before start , keep battery , glow plugs & pump in order and vehicle will never decline to start in temps upto -15 C
please wait for Xulfiqar for further insight.