Ahh - your clarification helped me see a point of confusion.
They supply the kit with a short arm allen key. You use the long end of that key for leverage. The caution in the directions is to keep people from using a regular pattern or long allen key from their toolboxes. The regular pattern wrenches are about twice as long, and my Snap-On T/L pattern tools are 4-5x longer.
Using the short pattern wrench they supply means you can crank down about as hard as you can without fear of over torqueing. I didn't go crazy with it, but it wasn't too hard to hit about 4 ft lbs if I judged correctly when using my Wheeler FAT wrench to do the final torque.