Intalling poly uca bushings

Getting the UCA's installed and having some trouble getting the bushings to fit. The UCA's are fine, no problems there. basically I'm having trouble getting the washers the form the end caps between the bushing and the mounting tabs on the frame rail.

Two of the bushings (drivers side front and pass rear) went one OK with some persuasion, but the remaining two I can only get the washer on one side. Any tricks to getting them installed properly? Seems like a little too tight of a fit honestly.

Prothane 4-206 Red Front Upper and Lower Control Arm Bushing Kit

Those are a pain to get the washers on. I have been known to hold them in place while installing the arms on the car...