Bug etching is areal pain!! Don't be afraid to use #80 at all. It's reallly a
final polish so you can't do any damage with it. I'd even try #83 on it with a polish or cutting pad. then step it down to #80 for a final finish. Do you have a rotary or just a PC? Depending on how bad it is a PC might not do it.
Hope this helps,
Brandon