Sust is generally a dealers choice due to the wow factor. "4 kinds of tests, i'm sold". But anyone that knows wtf they're buying, doesn't bite. Your case may be different due to availability, so make the best of what you have IMO.
You can definitely leave the deca out for the first run, that's a smart suggestion actually I hadn't thought about. He makes a good point that if something goes wrong, or incredibly right, you won't really know what caused it. Dbol the first 4 weeks is a good idea though. And for future reference, yes you can mix different types of stuff in the same syringe. Been doing it for years, no problems. I'm a little hesitant as to mixing oil based with water based due to a myth that has been going around on the boards for years of developing some sort of cyst, but I've yet to actually see or hear a case of it. I also am paranoid enough not to risk it.