In terms of increasing the distant to the original output.
If you churn twice, and every input you reference came from transactions that used ring size 7 (where one of those transactions would have been your first churn transaction), then your anonymity set would be 7^2 = 49.
You're therefore far better off making two transactions.
If you'd made 3 transactions, your anonymity set would increase fo 7^3 = 343. If some of the transactions referenced had used a ring size lower than 7, then your anonymity set would be smaller. To determine the anonymity set size when ring sizes are not uniform, you'd have to add together the tree of possible outputs that would be formed by the references to past transactions by your transaction.
Note that this technique relies on churn transactions not being easily detectable on the blockchain. If you churned 10 times in a row in quick succession, this might be possible to detect. Churning is a matter of ongoing research at the Monero Research Lab.