I just went through this on my fox when I upgraded to a Terminator rack and pinion. After the install I still had a great deal of slop in the steering so I went through everything to try to eliminate. Here's my list working up from the tie rods to the steering wheel.
1. Loose tie rod ends can cause slop.
2. Worn out rack and pinion. If you disconnect the steering shaft and turn the rack by hand it should engage immediately.
3. Pinch bolt securing the shaft to the rack. It needs to be tightened.
4. Not familiar with construction of an SN steering shaft, but eliminating rag joint with a solid shaft.
5. Pinch bolt securing shaft to steering column. Needs to be tightened, then tightened some more.
6.Upper bearing sleeve and bearing on steering wheel (in a fox)
Basically, torque the **** out of everything. A little bit of play in any of the areas translates to alot more at the steering wheel and seems to compound itself as you go up the line. You can effectively ignore the torque specs for these items. IRC even the instructions for the MM Hybrid shaft say, "may require additional torque." Once I had everything tightened and my arm looked like the hulks, the steering felt like it should, firm immediate input.