Pull if forward as far as you need mate. No negative in going too far forward. Plenty of negatives in crashing into a unit. Bays are designed that you can get off without crashing into the trailer/unit next door.
That being said - if you go forward and don’t have enough space you should be going slow enough to stop and sort it out. Revers a bit - and go and tell someone it needs moving. If that means you have to wait no big drama.
Generally, you have loads of room going forward to get out in my limited experience. In your own yard… not so common. I’ve literally had to get out and check 10 times when I’ve had trailers in front of me at an angle and a trailer next to me just inches away.