Fot your first run use 200mgs/week but For an experienced user 400 - 600 mgs/week. Some people say you can get away with less but I have not found that to be true at least with myself. It is easy on you, so I would tend to go the extra mile and take a little more when I can find it.
Deca-Durabolin is the "jack of all trades" when it comes to steroids. This is "the steroid" to stack with others. I am convinced that using deca with other drugs is where the term "stacking" originally came from. Deca is typically stacked with many things like dianabol, any of the various testosterones, sostanon 250, anadrol 50, etc, etc for adding large amounts of muscle mass. It can be taken along with anavar, masteron, parabolan, primobolan, etc. if you are looking to add better quality muscle that will stay with you longer and make you look harder since you will have less of the water retention associated with the dbols and testosterones.
Deca-Durabolin is a relatively safe steroid. Typically, you can expect a little minor acne, higher blood pressure which causes a longer time period for blood to clot, headaches, and increased libido.
As for PCT i would go with some Nolvadex and Clomids but its totally up to you