About time for me to change the oil in my Massey 1529 for the 1st time (got the 50h service free w purchace). What type/weight oil are ya'll using ? The manual says SAE 30 and 10W 30 in the same column ?This has me confused. Also mentions 15w 40 for warmer climates. I live in NE Indiana where you get hot summers and cold winters. My tractor is garaged and has an engine block heater that I use in the winter months. Any opinions and suggestions would be great. Thanks in advance.