i think the best choice would be the tunnel, but the exit should be 50/100m after the chicane and on the right side of the road, so cars that are coming on the track will not be on the race line.
but someone correctly said that for Blackwood in reality a tunnel would be too expensive, so it wont be a good solution.
exit before the corner would be a lot more dangerous because the cars on track go from the right to the left side of the track there for go to brake for the first corner.
in my opinion, the pit exit should continue from where is now, pass the chicane on the left, and the exit should be at the end of the riddle exiting the chicane. in this way cars that are coming from pits are faster, and those on track can see if someone is coming out of pits. and there is a very little band on the right before the highway bridge so the pit exit doesn't disturb the ideal race line.
it would be a VERY LONG pit lane, but more safety
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