That setup sounds workable, but dual screens is almost non-negotiable for me because it allows entire sets of primary/secondary windows to be mixed and matched

That setup sounds workable, but dual screens is almost non-negotiable for me because it allows entire sets of primary/secondary windows to be mixed and matched on the fly just by changing spaces (I use macOS primarily as well). It's very powerful, because it cuts the overhead of window management down to almost nothing without adding any key shortcuts or gestures beyond what I'd be using anyway. For snap functionality on the rare occasion it's needed, I use Moom because it's probably the most unobtrusive of those types of utilities. No Aero Snap to unintentionally activate or draw spurious rectangles and no extra key shortcuts, just a little bubble that pops up when hovering over the green traffic light. macOS also has very similar snapping functionality built in so when working on a stock configuration system I'm still mostly at home.