It's hard to answer because what would a dollar be worth at the time you want to sell? I would say todays value of 40+ and I might start selling a little at a time, just like I stack but only if it seemed overbought at that price and only if what I was selling into was a stable currency otherwise it doesn't matter what the price is.
Would you sell an ounce of silver for 1 million Zimbabwe dollars when it was inflating 10x a day?
So many moving parts to the world economy that it's hard to track your progress, at least for me.