Always assemble rubber bushes with plenty of rubber grease in the eye holes & shackle pins. If useing poly/non rubber bushes I assemble with graphite grease, it makes a bit of a mess but can be cleaned up when finished, better than squeaks.
I don't tighten the bushes up totally untill I have set the vehicle on the ground and bounced the car several times, this makes sure that the bushes don't bind up and not squeak.
If you have a 4 post hoist then you can bounce the car on the hoist before tightening.