Hello,
I know it's a bit old thread, but see it now, just a few thought.
US T-Bond-Cash you trade with CMC is not 10Y-note, it's (like it's name says) 30 T-Bond.
I have also a recommendation - trading this as CFD you are paying the spread (in this case 3.0 so it's about 1 ZB tick. I don't know if you are more long-term trader and you don't care. But if you are not, it's good business to go with futures and using limits if you can. Those "little" differences will sum up.
About the main question - trying to "think soberly" using economics rules is not so valid anymore. The markets are so depend on each other, and there is so much capital involved that you can't think about it like independent instrument. Like said before in this thread, after March there are some new correlations, there are some old that are stronger. In this case gold is nice example.
But do you need to know all that ? It will be nice, but from the other side there are very good traders, who know very little about their markets.
Just do your job, if what you are doing works in longer term, then you are doing good job, if not, then you need to think where the problem is. In meantime if you growth your knowledge, that's good. And trait it like a business. Check how much you gave up in spread and what part of your total profit it is. Also be prepared that if you growth much, then CFD market maker won't like you much and the problems can begin (of course they will tell you they hedge you in real markets etc., but you still are risk for them).
