36 hours estimated.
Does this estimated time actually turn out to be more or less correct?
Not even close. I just made a payment with BitPay. Blockchain.info said it would take 20 hours, but it confirmed after a little less than four minutes.
With a low priority transactions, confirmation time is basically luck. If you looks at TF's wallet, you'll see that after every 10 to 20 unconfirmed transactions, there suddenly is a confirmed one.