When it's wise to second barrel bluff on low stakes 5-10$ HU sngs

[Kamppi69]

Let's say i raise from the button with A9. Opponent calls and i miss. There's a heart draw on board but i havent got any outs except an overcard to the board. Is it wise to second barrel against tight opponent if he calls on the flop?

Also, i think it's like a no-brainer to second barrel if i
have no info about my opponent. But if i see him fold when im betting to my top pair, is it correct play to start to fire again on the turn. and is it like half of the pot on the turn or more (maybe 2/3) if villain calls on the flop with like 2 hearts on board. Semibluffs of course but what about stone cold bluffs. Third bullet is like a no brainer but im intrested in turn play.