Nasty job. Since moving to the Southern US I have vowed to never again do that kind of rust repair though I did plenty of it when I lived in Michigan (that's a heavy salt use area). Around here, rust-free sheet metal is not hard to find so why bother? The 240D that I scrapped was WAY better than the car you're working on but no one wanted it so off it went to Pick'n'Pull (I bought it for the manual trans, which is in the S-10 along with the shifter). It was crushed long ago.

Dan