Interesting. I didn't know you could fire the P7 that way. I wonder how accurate ... that would be.
About the same as any DA gun, in my experience.
I've done it in IDPA for speed - it is not a preferable method, but is effective in close defensive shooting.
I went DA/SA with decock. Simple, accurate, but enough of an initial pull for an added measure of safety that something like a Glock lacks.
I don't like safeties on reactionary guns - just something else to go wrong.