so how tight this should be? there are two nuts (for 1" and 28mm wrench) that press against the bushing. I found somewhere that OE torque is 60-80 ft.lbs - isn't it too much for PU not to crack? should it be rather 60-80 in.lbs?
Do you already have the PU bushings? If not, stick with the rubber. PU is too stiff for the strut rods, the bushings need to be able to flex with the movement of the suspension. PU bushings will lead to things breaking.
Every set of strut rod bushings I used have had a metal sleeve running through the middle. The big washers hit the sleeve before the rubber is totally compressed so you are really torquing against the sleeve.