[djr]

I'd consider raising both 3rd and 4th. On 3rd you've got great bluff ability with a good drawing hand if you can get this heads up you're likely to win on 4th/5th if your opponent(s) blank. On 4th you really need to try and get the BI out of the hand as well as your hand is strong enough that a raise here is for value.

I don't fold 5th, but I'm a fish.

I don't know that 6th is a raising situation. You're likely to get 3bet if he has a boat or is trying to bluff he has one. I'd generally just check/call this down.