Additions to secondary

Any help would be great. I have a Cream stout that has been in the primary, thinking of adding espresso to it, and from my understanding, I should brew it as I was gonna drink it, add it to the secondary, siphon from the primary and let sit for 1 week. Well, How much brewed espresso should i shoot for? any thoughts on infusing the espresso with maybe a vanilla bean or maybe some hazelnut flavor? Thanks for your help in advance.

Mmmmm hazelnut. I was thinking of doing this soon as I'm still working from kits and there doesn't seem to be much out there for coffee stouts. There's a few threads with some good info if you search coffee in the secondary but there's so many and so much varying advice. Sounds like cold steeping the coffee is the way to go? maybe? maybe not?

I hate to add questions to someone else's thread, especially without having answers to any of the ones already provide. But assuming comcast doesn't mind the slight hijack/addition, information regarding how long the various methods of adding coffee end up needing to mellow out would be greatly appreciated.