After a bit of thought, I came up with a way of making accurate ellipses Alias Sketchbook Pro. Its a bit of a round about way of getting ellipses drawn but it works just fine.

Start out by creating a face in perspective that we can put the ellipse onto. A square neatly fits a circle inside so its easy to judge its position. I have used a basic cube as shown.Now create a new paintbrush. Creating a custom brush enables all settings in the brush settings menu, as opposed to the few offered in the preset brushes.

Now change the settings on that brush to create an elliptical brush shape that will fit neatly on the side of the cube. Key adjustments are Size, Slant and Roundness. Also ensure you use Hard edges to get a crisp edge on the ellipse. Click the brush once (on maximum opacity) in the right place. You need to remember the settings (slant, size and roundness) because we will use the same on an eraser tool to cut the middle out.

To make the eraser tool, create a new hard eraser, and set up the shape to be identical as the brush used in roundness and slant, but make the size slightly smaller - again with hard edges. Click this once on top of the brush blob to delete out the middle. It is faster to use a

white paintbrush but an eraser works better because it creates a transparent cutout, not a whited out cutout. Because it erases stuff, you may want to build your ellipses on separate layers so you dont erase off other work behind your ellipses. Individual ellipse layers will mean you can copy/paste flip, move and scale them also.

I set up the names of these new tools as A and B, which helps find them quickly from my custom made brushs pallete.

Hope this helps