I annealed it 2 - 3 times during sizing, I found it really helped, without annealing it was be really hard to roll it down and wouldn't go down as much. I put it on the fire brick and run my torch across it and it would glow bright in no time. I was wondering if smaller but more steps would cause more work hardening rather than fewer but bigger steps. At any rate it's time consuming but fun to experiment.
Zinc worked too and was easier to work with but it resulted in micro cracks, I am not sure if its the copper plating causing that or Zinc is just simply not malleable as copper. I also tried to anneal Zinc but as expected it melted quickly but I do think it helped as it resulted in smoother surface from the part that wasn't melted. My daughter had couple hundred pennies in her piggy bank and while 1983 or earlier penny is not rare but is not common either.