I think with nearly every regular/semi regular playing with PT/HuD balancing is taking on a bit more importance at 50NL. Granted most won't know how to use it (or use it well) at this level, but they will have some numbers on your play.

I was going to say that if you have a bit more than a PSB behind when the action gets to you in situation 1 then shoving would be best, but that probably means that there has been a bet and a raise already for the pot to be so big. So you aren't going to be folding out many hands, and you may not have as much difficulty getting paid if you hit the turn.

More important would seem to be position. If you are last to act then you can more easily get the money in over the turn and river, while limiting losses if things go awry in both situations.

Both situations could easily be +EV for both players depending on how much money is behind. If you are a favourite to win, getting AI is +EV. If you are getting the right odds on a draw then it is +EV. More important than just having a positive expectation though is maximizing the expectation for the given situation, and I have very little idea of how to do that.