animal_mother,
I to am about to start a sust only cycle (my first cycle as well). But I am 24. I have been researching this a lot and have been debating between 250 and 500 a week. After PMing many people who have done sust only cycles, I have decided to go with an 8-week cycle with 1CC every 5 days. In every PM response I have gotten, I have been told that most people on this board tend to recommend way too much. Many say that this is too weak, but others say that for a first cycle it is sufficient. Although this board is a great source, it can also be very confusing as well, because everyone has their own opinions, which can sometimes be overwhealming.
Just PM some people who have done sust only cycles for their first cycle and get some input from them... thats probably the best thing you can do.