The brass tube will work fine. And, with epoxy and clamping, should never fail. This is how I have the inboard flap connected to the outboard flaps on my TF AT 6. Two servos operating 3 separate flaps. I would advise two small brass tubes, though. One at the LE, and one out close to the TE (as close as possible, where it isn't too thin for the tubing!
Good luck with it.
I just started my giant stick build last night. Two hours, and I got one half of the wing done. Two servos, soldered wire extensions, and soldered pushrods. I'll do the other half tonight, and look forward to flying this thing maybe next week. You did notice the change in CG in the addendum, didn't you?