IMHO with poly 9 out of 10 times it is going too aggressive. Just don't lol
Here's a simple way to pick. Call a friend over. Stand with your feet spread about 18" apart. Have your friend kick you in the nuts. If you get up in 20 seconds or less, get the harder bushings. See ... no need to have to change to less aggressive bushings - that test is foolproof
But agree with the ability to replace if worn out, etc, definitely a nice design.
Filippo