Intermittent steering shake

I picked up a Lincoln Ls 2002 a year ago, ran perfectly until I took it to sears for a wheel alignment.They gave the car back with a missing lug and 2 finger loose lugs on the same wheel, felt rim slapping the rotor on the ride home (found these problems 5 miles away) Took it back next day to get lug replaced and recheck alignment due to shaking in steering wheel- tried selling me on rack and pinion. Later found out they had sandwiched 2 hub rings together on one rim, and sandwiched the retainer rings for the hub rings between rim and rotor on one wheel (duh). Anyway took car to ford and they coundnt figure out why steering wheel was shaking, they checked wheel alignment and balancing of tires (felt like front passenger wheel is the problem).Since then had all new tires installed on my same custom rims and balanced. Still feel front passenger side wheel shaking. This problem seems to come and go, usually hits around 45-50 mph. Cant seem to figure out the issue. Anyone have any suggestions?
I’ve also got the stick on weights because the style of rims, is that harder to balance? One rim has a few weights while another has weights stacked on top of each other.