The fib circles can be used as an ellipse. I found you have to drag on both ends of the line, alternating like wheeling a clock, pushing and pulling. Really the best way to set it up ellipses or circles is have a box that shows and move the sides, top and bottom or diagonal corners. I can fine tune positioning and aspect to a tee with "Kyplot"... but it doesn't have live feed and other things. This is a great site but I would make some custom tools myself.
EG. Right Diagonals. If you laid out an X from 4 points and the computer automatically scaled the X so it became + right angles as on the chart. From one center, click on two points and the ellipse automatically shapes to fit. Proportional boxes that can be dragged from sides, top, bottom and corners and gives a readout of the height to width ratio.
I have pics in "ideas" on these topics. Just need the right software.