There is a lot of variation between ports in how things are done. I have not done much ship docking in recent years, but I occasionally do some. It’s always with conventional twin screw tugs. It’s been four years since I’ve towed a barge with a single screw tug, and about 30 years since I’ve docked a ship with a single screw tug. I’ve never run a tractor tug.
Typically, the pilot will tell the tug where he wants it positioned, and what, if any, lines to put up. The pilot will tell the ship where to put the lines from the tug. Often the tug captains and pilots work together all the time taking the same, or similar, ships to the same berths. Each knows what the other is going to do, and when, long before it happens.
Sometimes nobody knows each other. Sometimes there is a prima dona pilot who makes things difficult. Sometimes there is a young tug Captain who has never docked a ship before on a tug that is not well suited for ship docking. Sometimes you have to work with the low bidder that’s available. In some ports there are very few ship calls and no tugs. The tugs may come from hundreds of miles away to dock a ship in ports such as Adak, Alaska.
A tractor tug will only have one line up. A conventional twin screw tug will have one line up, and possibly a second line to the outboard shoulder bitts. Both lines may be in the same chock on the ship, or the outboard line may be one chock forward. The use of single screw tugs for ship docking has become uncommon, except for “hold in” jobs, but a single screw tug would probably put up at least two lines and maybe three.
The most powerful tug will usually be placed at the bow. The further forward the tug is the more leverage (turning power) it will have. Pushing against the bulbous bow, if possible, works well.
Personally, I don’t like being positioned under the anchor, especially with a line up, and especially approaching a dock. Obviously, the tugs need to be positioned where the mast, wheelhouse, etc. will clear the flare of the ship. Where you can keep clear of the flare also depends on the speed of the ship, current, etc.
Ship docking is best left to tractor tugs and people who work together in the same port and do it everyday.