I did the same in my XJ. But I needed to get them on in 1 hour so I didn't really have the option of pulling the springs (I'm not that fast). So here's what I did:
I cut a 3" circle out of 1/4" steel. I drilled and tapped that piece, then welded it to the bottom spring pad with the spring still on (that was interesting). I drilled out the Hockey Pucks and countersunk the top puck so the surface would be flat. Then I put each puck in the coil then screwed it in. I'll paint it later when I have the spring off.
I figure my tack welds will hold better than epoxy.
The only force on these is compression. There's no lateral or tension force so it shouldn't take much to hold them in place.
Another option might be to drill your pucks for a bolt, then countersink both the top and bottom pucks. Put them into the spring then hold them together with a bolt and nut. They will bounce around but rubber doesn't exactly *clang*. If you have 2 or more they wont be able to fall out, although, it might flip on it's side. I'm sure with 3, they would stay upright.
"Working with cars is a little like a really awesome date: you start out expecting this to be simple and straightforward; four hours later you're laying under her, panting and cursing, and things are a lot more complicated than you thought."
I drove okee ('92 XJ)
then I wrecked him...
I drove rokee ('93 XJ)
then I rolled him...
I drive Clifford ('79 J-20)