I've never messed around with copper strips either, but your foam insert experience sounds pretty familiar. I gave those a shot a couple years back, a...

I've messed around with both synthetic and traditional felt over the years, and honestly, I haven't noticed a huge difference specifically for ice dam...

I had a similar experience with peppermint oil at my place. Smelled great for about a day or two, but then the squirrels were back like nothing happen...

Totally agree on ventilation—can't tell you how many times I've seen storm-damaged roofs that could've held up way better if the attic had proper airf...