On the diagonal!!!
Marc in Luxembourg
>Joe,
If the stile is proud of the rail because you wanted it like this, I would smooth before I assembled.
In case the joint is to be smoothed afterwards because it doesn't fit one hundred percent, I'd smooth the piece proud of the other on the diagonal beginning my cut each time at the joint (indeed about 1/4 from the joint) the blade skewed to the piece to be planed. Firm pression on the toe of the plane when starting helps much. This way you can "feel" when stile and rail meet in one plane. The last shaving should be one where you take off from both pieces. If you don't start behind the joint, you risk to have tearout in the second piece, because the plane's blade cuts in the idle immediately behind the joint and will dig in abruptly a moment later after the heel leaves the higher piece.
I use my best smoother with a high cutting angle up to 60 degrees, small mouth opening, because of the difficult grain. I wouldn't use a coarser cutting plane because of tearout. Using a block plane, it should be tuned to the same cutting geometry. For the last shavings using a scraper helps, but the blade should have rounded corners in order to prevent tracks.
Regards,
Marc,
doing the same thing here over the pond on american walnut and trying to avoid this same scenario ;-)
P.s.: I'd enjoy to see some pics of the finished piece :-)