It wasn't too much trouble, I ran two sullivan semi-flex rods, and used the two outside stock servo mounting locations for each elevator half. Make supports for the rods that glue to the formers inside the fuse. Then you just have to relocate the throttle servo, which I placed on the left side just ahead of the other three. Now I have very little play and dual servos for the elevators. I cut the covering out of the holes in the bottom of the fuse to gain access and then recovered the bottom. It's pretty painless actually and the results are worth it.
ORIGINAL: *Crash*Johnson*
I had this same dilema with my CG Ultimate 60. Went with stock hardware and single servo. There seems to be a bit of play on one side so I'm thinking it's definately better to use dual servo's if the option is available.
With my arf it'd be a pain in the arse to do dual servos so I went stock, but may have to redo it to dual down the road.