From the reverse angle, you can easily see the small notch carved into the stock rail.

To carve the notch in stock rail, I put the points in the straight position, then use a small thin file and carve a notch in the adjacent stock rail. This provides a place for the points to 'sit' into, and thus provides a smooth path for the wheels/flanges.

Sharpening the points: Do it by simply filing carefully while blocking and supporting the switch points with some rubber or something to keep it from bending while filing. I bought a set of inexpensive micro files, nothing fancy or expensive, but all with a very fine tooth and various shapes. I find I only need to shape the diverting points, the straight points on all my #4 Kato turnouts were fine. File the points down to a 'triangle', i.e. take the top edge off and then taper the point. Hope this crude graphic helps illustrate what I mean.

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Do it by simply filing carefully while blocking and supporting the switch points with some rubber or something to keep it from bending while filing.