There are a variety of things you can use. I happen to use a LED Lantern. When I set it just so in a difficult backing situation when it's twilight, or dark all I need to do is aim those tandems and ABS light at the corner directly towards that light I put there. I sometimes use fireworks chemsticks. I have a box of them still. They are useful for lighting or being able to tie to a long string to spin over your head for Air amblance helicopter to find you in the dark. They can see those for miles.
Glad to know I'm not the only one who sometimes has difficulties at wide open docks lol. There's a couple places I go to that has covered docks, and those are hard to back into, it's like backing into a black hole. When it's sunny and bright outside, that's when it's the hardest, I cannot see where the back of my trailer is once I get about halfway in, usually takes me 4-5 pull ups to hit the dock squarely. When it's cloudy or overcast, it's not as hard to see where the tail of my trailer is. One of the places said they know it's hard for drivers to get backed in and they're going to put some bright L.E.D lights on each side of the dock plate for the drivers to see.
I've had that happen a couple of times back when I was bumping docks. The issue is there really isn't anything to gauge your movements off of like there is when backing between 2 trailers etc. I back multiple times a day now, not to docks like LTL, but to paving machines doing highway work, and it's all at night and sometimes pretty significant distances, on sketchy terrain depending on how many trucks are in line. It's definitely interesting at times. There are no reference points, just darkness with a bit of light provided by the portable lights they set up, and the only thing you're aiming at, is that big machine way back there with a spot light on it facing your mirrors half the time, which is real #####. Really throws off your vision when they don't have that marker light set correctly.
I had to hit one on a tight lot with no lines.Was going pretty good,but missed it by that much.Had a heck of a time trying to get my trailer over.Got it lined up,but was jackknifed,so I had to unhook,then straighten out.Those are docks you “Do Not” want to forget to open your doors at.