Rob,
With the standard drop in switch track 036/045/054 you are correct the closest you will get would be using the 054 turnouts. I made a quick design using the pieces you would need to get the best fit without making custom cuts. There is a mix of smaller standard straight pieces in the design, 6015, 6052, 6053. Although there is a slight misalignment in several joints when you connect it all together it will not be noticeable.