If you have a cab heater, the 743 parts book calls for a tank style engine heater that goes in the heater circuit. It will heat the whole engine, it works on convection, and they are generally easier and less involved to install.
The freeze plug types have a rubber surround that expands with a bolt, similar to the old thermos bottles. The biggest problems with them is leakage due to improper installation, uneven heating due to location, and clearance issues which is why there are so many different applications.
The lower radiator hose has great heating efficiency, but requires complete draining of the cooling system and cutting a hose that generally has a spring in it to keep it from collapsing. Depending how low it hangs, it can also be vulnerable to snagging from below, or an improper secured cord being drawn into the fan.