My lower links are seldom at the right width, but I don't think of that as a problem. Even if they were at the right width, I think I'd spend a lot of time trying to back up 'just right'.
Much as Bird said, I just back up so I can lower one link into its pin slot (or over the pin if the pin is built into the implement) . I then make one pin (with the engine off, of course) and just spread the other link by hand over the pin slot. Most times, the link drops into the slot, but a combination of lowering the 3ph and using the leveler will put the second pin in the slot and roughly line it up.
Usually, the tractor isn't quite square with the implement so the link and holes don't line up enough to make the second pin. I use a 5' wrecking bar to move the implement into position. In fact, the wrecking bar and keeping implements on blocks (so they can be moved easily with the bar) are the most useful things I've found in changing implements.