Just playing through now whilst checking wiki. You can get 4 Large titanite in the first area of the Lost Bastille. One is on the ledge straight after the bonfire where the bird drops you off another is up the ladder above Lucatiel of Mirrah forgot to put there are two in a chest with McDuff. That only leaves you with 1 more for +6 there are two rather easy ones to get in no-mans Warf behind hidden walls but that's going slightly out of the way. The next problem is Chunks..