I have leaded 1/4’s back in in the past. Thinking that was the way they were done originally. The problem about 3years in it starts showing some warping. It’s very minimal but is noticeable at the right light or angles. When you think about it what did the original leaded panels look like years later? I’ll tell you they are warped and look like crap. So I don’t know why I thought mine would look any different. So now I use All Metal Filler is an aluminum based filler & works very well. I have cars out there that has been in there for about 5 years & still looks good. I know some guys use other stuff like kitty hair filler & such. But I only have experience will the aluminum based filler. Good luck with your project.