3-bet the Turn and River, or just Call?

[Siegmund]

The only thing I find strange is bet-call, bet-call on the last two streets.

You aren't sure if you're winning or losing this one ... so pick one. If you think you're winning more than half the time, you would 3-bet the turn and lead the river ... if you think you're not ahead, you are only going to check-call the river.

I'm not sure which line is right - but yours is, as they say in backgammon, not thematic.