I have hunted with several hammer doubles over the years. I carry them with the thumb of my right hand over both hammers with the right hammer almost in my palm. That way I can cock both hammers at the same time as I'm mounting the gun. However, since I have a dog, I'll usually cock the hammers back just using my thumb when I see my dog getting "birdy", releasing the hammer(s) when the situation has passed.
Steve

Approach life like you do a yellow light - RUN IT! (Gail T.)