Edit: Sorry, I wasn't clear. I am talking about welding steel before galvanizing, so as to minimize "coating growth", where the zinc gets deposited thicker on top of welds than on the parent metal and makes welds appear even though they are ground flush.
I found Matt's advice in an old thread on here:
"It is still better to use high silicon wire if mig welding as the zinc will have a high build on regular wire....as in if you grind anything flush the weld will show through"
However, everything I found online says to use low silicon wire, or wire that has a similar silicon content to the base metal, since silicon actually attracts zinc and will cause a higher deposition rate on the metal.
I think Matt may have just gotten in backwards in his post.
I think ER70S-2 or S-3 is likely what I want.
Anyone else have experience with this? Not so much an issue unless you are making butt joints or lap joints that are ground flush.