Tool Outline Color

[wesmat]

How do I change the tool outline color?  When I search on this I can't find the answer I need.  My need is when doing very detailed edits to gray toned images it is very difficult to see the tool size, which is made up of alternating white and black marks.  Specifically the pencil, airbrush, smudge, etc. It is very difficult to place the tool on a gray area next to an edge.  For instance, if I want to draw a line on a grey area and have it touch another line, I have to zoom in to  see when it is touching.  For this case I'd like to change the tool color to a contrasting color, maybe red.

I have attached an example and the pencil is located in the gray next to the white a little to the right of center.  I find it easier to see in the capture than while editing.

Thanks