Over the weekend, I welded in this patch panel. Overall, it came out decent for a beginner, but the horizontal seam is puckered in some, due to shrinkage. I'm a novice at auto sheet metal replacement and a newbie at hammer 'n dolly. Can I alleviate the puckering via hammer n dolly, and if so, which side do I need to be hammering on? Also, what type of hammer and dolly should I use? I removed the quarter window tracks, but space is still limited to swing a hammer on the inside.