Replying to Mounting Donner Parties

I hate to make this thread, because I get pissed at them too, but I am in a bind. Just got a pair of 09/10 donners for 300 bucks (stoked), and they suggest -5 from center, I was thinking -3, or something a little closer to center, they have that equal rocker in the tip and tail, and the tail is only 5mm thinner that the tip, I love to ride switch in pow, but I also dont want my riding to be fucked up from such a foward mount. Let me know. Thanks