Thank you all for the responses!
I don´t think about the color of the primer, I just take one from the shelf in the store. Now when you told me, you are absolute right. No good idea to put white over gray
I have to buy a white primer for the coming painting of the main body.
Cato: Yes I can start a build thread in Big Boyz, I have one going in another forum but I can make a summary and keep it going here.
/Bo