With a clean shot I'm able to make it with mine and, other than the flipper bats and rubber, all the mechs are original. Are your bats, maybe, adjusted too low? Is your coil voltage low?

I wouldn't think so but the more experienced can chime in. The bridge converts the AC to DC. Either it works or it doesn't. This was still the days of 25 volt flippers so you're getting above factory spec which should be enough. Just for experimentation, have you tried adjusting the pitch? I don't know the degrees but my back legs are appx. 1 3/4" from the floor to the bottom of the leg. The fronts are all the way down except for the support nut.