I start by making relief cuts along each fillet.

Cutting in the push position, with my thumb behind the guard and one hand on the molding, provides precise control of the blade.

Don't push the tool into the molding. Cut forwards by tipping the back of the motor up and angling the blade into the workpiece. That's the only way to have complete control over the depth of cut.

Cope tight beads from both directions, angling the blade slightly and undercuting as you approach the bead.

After making relief cuts, wave the blade back and forth inside the bead to remove any remaining waste.

Cutting along an ogee or tight radius is easy as long as you use the right blade. The Bosch 244D blade, with wide set teetch, cuts a kerf much wider than the shank of the blade, allowing the blade to scroll more easily.

Hold the saw in the pull positioin, with one hand on the molding. The top of the chair rail looks better with an overlapping miter, rather than a butt-cope. Start the cut by pressing the shoe against the bottom of the molding, then tip the blade up into the miter.

Make the overlap about 1/8 in. thick. Cutting parallel and straight is easy if you tip the back of the motor up into the workpiece.

Back the blade up slightly and clean out the top bead by making an additional kerf; wave the blade back and forth inside the bead to remove the remaining waste.

Switch back to the push position to cut up through the larger ogee in a single pass.

I slide my thumb back on the saw guard as the cut deepens and the tool disappears under the molding.

I cut a relief miter in the previous piece at my sliding miter saw, making repetitive cuts while holding the saw at approximately the same depth. The actual depth of the relief doesn't matter--cut it a little too deep, because the cope will cover the miter as long as you don't cut deeper than the top cyma reversa curve.