going into mutilateFollow

k so my rogue is coming up on 41 point talents and i allways wanted to do muti at that point, i know the general trend of cookie cutter build but i wanted to know how to go about it.

I lvl my rogue with my friend's alt enhancment shammy, he outdmgs generally me just through better gear and he's good at the class. I'm currently combat swords speced, stopped at 48-49 doing bg. I honestly like the spec but I started rogue invisioning going mutilate anyway. I am aware of how much better swords are for general solo and PvE play but in a duo with this shammy it doesnt make much difference cause the mobs drop so fast between the two of us.

I was wondering for this duo set up would it be better to go straight combat muti starting right the bat at 50, or should i wait till 55 and start putting points into opportunity for the dmg bonus?

Thanks in adv.
Dales (yea thats my rogues name, theres a story behind it if your curious)

Muti damage is gimped unless you spec either 5/5 opportunity or 5/5 DW specialization. So lvl 55 is better than 50.