Looking for info on handling under power...
As long as there is no current, slow is good.
If there is a strong current you must use enough power to remain in control of the boat. A center control point(center line cleat) is very handy. If you tie up the center of the boat to the dock, it won''t move much until you can get the fore and aft lines on. Also a rear spring line is very handy. This line runs from the outside end of the dock to the centerline point.
You come in under power, get the aft spring line on. As that line tightens it pulls you to the dock. If needed you can leave the motor in gear allowing you to go forward and get the bow line secured.