France doesn't have any CB against me, at least. The difference in size is abstracted by a malus in relation, -26 for me, which would probably mean I'm a quarter of their total power. The wiki is unclear about that, so I wondered if anyone had a definite answer. I guess I will try that and return here in a few days when I will have the answer. I will also try the questions thread. I would really like to know in what I will be, in order to not take unconsidered risks and finish in extreme trouble.
You are probably right, tought I'm trying to be elected emperor, so I don't want to too much affect the balance of the HRE (balance which I think I destroyed...).