I've made a lot of curved pieces like this over the years.
What you've done looks good from where I'm sitting.
I would start same as you, thin kerfblade in the tablesaw and take off that top profile.
But then set the blade depth stop on the sliding chop box and do a series of parallel crosscut kerfs on the b-side of the board deep enough to leave about 3/16" of the a-face every 3/4" or so. This will let that clean grained base board easily bend to that curve, but still be very solid.
Then reapplying the top profile piece that was ripped off, will hide all the kerfs made on the top of the base piece.
I've actually had lots of clients pay me for this type work. But it rarely was on a "normal" house.