Nige_S helped with this macro. Works well enough for my current use case, but would be easier and better if duration for a "Move and Click and Drag" could be set. As it is now, the drag is "instantaneous." I wanted it to be faster but each repeat took a certain amount of time, but I wanted the time resolution.
Enter the desired drag distance (in pixels) into the first green action. (See TIPS, below.)
Enter the desired duration (in seconds) into the second green action.
Adjust the number of pixels each step will move by in the first blue action. The smaller the number, the smoother the movement. The smallest possible number is 1 pixel.
Adjust the step pause length (in seconds) in the second blue action. The smaller the number, the smoother the movement. The smallest possible number is 0.01 seconds.
With your mouse at the start position, trigger this macro. The number of steps required to cover the desired distance will be automatically calculated and the click and drag will begin. At the end of the drag, the mouse button will be released.
1. Working out the desired distance in pixels:
One way to acquire the desired drag distance in pixels is to use the screenshot tool. Click and drag from the start point to the end point and make a mental note of the X/Y-axis pixel numbers beside the crosshair. Hit escape to cancel actually taking a screenshot.
Another way to get relative coordinates (i.e. the distance between two points in two dimensions) is to use a macro like this: