This is probably the most difficult decision I tend to find myself with and my decision will be based on how the game has been played, how much I fancy the shot and how nervy I think my opponent is. If you are playing someone who is confident and seems to be playing well or you are shooting well yourself, then having a shot is perfectly playable.
However, it is a very long shot and it should be your last. In this particular scenario, I believe that the percentages slightly favour a defensive line of play. If I shoot, I win c. 16% and I think I'm going to win over 16% of the time if I don't shoot.
So, where do we go? Level with penult has been suggested as has C2. Let's look at opponents next turn. They rush to 4-b and try and get a rush to penult. If they finish short, I don't want them to go "Hey look, I've got a nice rush to the ball in C2 – yippee!!". Don't go anywhere that gives them increased rushing angles, particularly in "safe" non-lift corners.
Let's say they rush to 3 yards north of penult after 4-b. If I have an opponent ball on a side boundary, I'll approach penult putting partner slightly on the side of the lawn that the opponent ball is. If I run the hoop nicely, I'll have a rush pointing 2 yards to one side of rover, if I over-hit my hoop shot, I might have a rush to the opponent ball. I can rush to the side boundary, take off to get a rush to rover and if things don't go right, my opponent will still need to hit a lift shot.
Therefore, my line of play in scenario 3 is to play into C1 and hope to generate a shorter shot than 30+ yards. If they rush to C1 at any stage, they'll be leaving a ball in Baulk if anything goes wrong. If I'm playing a top 5 player, I'll probably shoot, but the next level of player down make sufficient errors, particularly when under pressure to give you enough potential reward to turn down your 16% chance.
It is perhaps important at this stage to note that I am playing for mis-play from my opponent. What normally happens is opponent rushes 4 feet in front or side of 4-b and approaches the hoop and tries to get a rush to penult. This shouldn't happen – can the non-minus players see why?
If you can accept that your next action after playing to C1 might be shaking your opponent's hand, then I believe it represents the best percentage play.