By using some code in Python console, you can quickly extend what you can do in the GUI.

1. To specify the size of Point Set: 

open a Python console, type
    p = 
then drag your Points annotation, you'll get something like
    p = orsObj('7acf60ba83bb495ca159bb9a5bf1990aCxvPrimitive_Points')
press enter.

You can then do this:
to see the current value, and 
(0.005 for example) to change the value. 

2. To specify the world position of a Point:

Again, get the object by dragging it to the console:
p = orsObj('2d3f420cd6fc422c9389821c8a01ecf3CxvPrimitive_Points')

You can then obtain each point's position by doing this:

pos = p.getControlPointPositionAtIndex(NN, 0, None)

where NN is the 0 based index (in the UI they start at 1)

You can change a position by typing

pos.setX( yourXPosition)
pos.setY( yourYPosition)
pos.setZ( yourZPosition)
p.setControlPointPositionAtIndex(NN, 0, pos, None)

Please note that units are always in meters in the Python Console.