No no, .999 is the purity of the coin. The 1/10th ounce coins should be mostly .999 purity as well. I assume you mean besides the 1 ounce coins.
You are going to pay more for ten 1/10th ounce coins than you are with one 1 ounce coin.
I think you guys should start investing in silver instead of gold, although it wouldn't be too bad to have a mix. But don't take it from me though, do your own research.