http://www.denttrainer.com This video is about a paintless dent repair glue pull repair that went totally wrong. You'll get a good reason why you shouldn't pull on a curved rail with a mini lifter but more importantly how to to still fix the dents and get paid. You'll be able to watch the full tutorial here
https://www.denttrainer.com/courses/deep-glue-pull-don-t-do-this