Under what circumstances would you use a metal filler, such as All-Metal, over fiberglass filler?
I just finished welding a new sail panel on my car. I had to do some repairs on the panel before I put it on so there are some weld seems. I dressed them as best I could, but they will need some filler. But more importantly there is a slight crown that I'd like to get rid of. The crown is slight enough and would be a big enough pain to work out that I'd rather level it with filler. Basically I don't have enough access to the back of the panel at this point to work it out by hand.
Should I use something like All-Metal here or just go with a fiberglass filler? In general is there any reason why I'd want one over the other?