Ball links are for sure the way to go, on both ends of the pushrodto the control horn, and to the servo arm/wheel. No soldering involved.

If you want to use the Showtime as a pattern-dedicated model (as opposed to a switch-hitter pattern on low rates and 3D on high rates), you should use servo wheels on your aileron and elevator servos, not the longer arms. For pattern style precision aerobatics you'll do much better with your mechanical linkage set for 15 degrees up & down on ailerons, 12 degrees up & down on elevator. Even that may be too much on the elevator. You do this by setting your transmitter ATV on ailerons & elevators to the maximum (125% or 140%, whatever your system allows), so that full stick on your TX produces full rotation (60 degrees either direction) on your servo. BUT by connecting the pushrod to the servo wheel instead of the long arm, your full-stick movement will produce only a short push or pull on the pushrod. Then connect the other end of the pushrod to the longest setting on the control horn, and see what you get for degrees of deflection on the control surface with full-stick at the transmitter.

If you're at the shortest distance possible from hub to connection on the servo wheel, and longest distance possible from hingeline to connection on control horn, then you have maximum resolution from your servomeaning a little bit of stick movement will produce even a smaller angle of deflection on the control surface. Now you have precise control. If your CG is set anywhere close to where it should be, you'll have all the control you need, and more. You'll also be using your servo torque to maximum advantage, for good control authority.

If the control surface is still moving too much, one possibility is to substitute a longer control arm. Short of that, you can reduce your ATV setting on your TX. If the control surface is not moving enough, move the connection on the control horn in a bit. To go back to a 3D set-up, take off the servo wheels and replace them with longer arms.