I usually set up #17 by dropping the ball in the lower right hand corner of the tee. Then I move the club to a point on #18 such that the "thumb" is in line with the bottom of the white end of the fence(?) and to the left edge.
Here's a poor picture of it. But, it usually works for me ... but, not always. If you fool around with it, it's a start, I hope.
Good luck!