This is the first time I have hooked up split elevators using a wood push rod with two wires on the back end. As long as both halves are moved at the same time, there is virtually no play. If you move one however, there is enough flex to move the other half the opposite way. Is this normal? It seems to me you can't really fix this play. In flight both halves have the same flight loads so it may not be an issue. As I am going to be hovering this plane it does concern me.
JB

I doubt the flight loads on the elevator will be very high while hovering. In fact, I'm sure they're less than in forward flight. I'm guessing though that you'll lose some control precision with the flexing.

Most planes I've seen being used for 3D have independant sefvos for each elevator half (bigger stuff), or the elevator halves are tied together with a rod and controlled by a single servo or a pull/pull set-up.
Dennis-

I agree with DBCHERRY here, most of my planes have split elevator and do have some play (my spit has the worst amount)

but it all depends on HOW MUCH play you are having i usually find (tested this myself) that once the elevator is actually operating it takes up the slack and you wouldn't really notice.

in flight i have never had any problems (in-fact the spit is more responsive to elevator)

although i would have thought the larger you control surfaces the more apparent it would be in-flight, i have noooooooo experience here as im not a 3D pilot so better wait for the experts on this one

how you guys do all that hovering stuff ill never know i stick with scale sports jobs i feel safe there