So this was literally 30 years ago, but on a bad PI I had, I made small slugs of aluminum, spend a couple of hours on a grinding wheel for interference fit, and tapped them in lightly, then a couple spikes with a prick punch to swage them in and they stayed forever. I like the idea of similar metals and some thickness to get a little deeper.
I don't remember how long it took or how much I had to modify the hole to get it done, but I don't remember it being hard