How does one kern Small caps?

How does one type or paste in small caps and old style numbers for kering? How does one type in small caps or old style numbers? How can there not be a post about this?

You type normal upper and lower case and then activate the small cap feature from the lower left feature popup.

You can also use Cmd-F to open a dialog to insert any glyph by name. (Not as convenient as using the feature menu, but will allow mixed situations, e.g. when you want to look at your oldstyle figs next to your lining figs.)
There’s also selecting the glyphs from the font window and opening a tab.

Buy Metrics Machine. Copy the caps/caps kern pairs to the small caps. Then use a transformation to reduce all smallcaps/smallcaps kern pairs appropriate. Then kern the Caps/small caps pairs and you’re done.