I used lucas on a free crown vic that the main seal was blown out of. Worked perfect, It went from lossing all the fluid in 2 min, too lossing nothing. And it lasted through the whole derby! Ive also used it to quiet cars with morning sickness. So far its been in my dads pos van for 3 years. No issues.
No stop leak ever unless you’re just driving it to the junk yard. That is unless you want to buy a power steering rack and pump later on, then by all means add it.
About twice a week I have to fill it up. I notice the loud squealing so I add about 1/2 a bottle of fluid and it quiets for a few days. I am only planning on keeping the car for a few more months but I don’t want to risk doing more damage if I keep it longer.