I see, thank you for the quick response!
Option #1 isn't really doable due to the low level nature of the values (they have to stored in statically allocated arrays indexed by an enum),
but option #2 looks workable.

If I have a single underlying model, and a QSortFilterProxyModel for each type (which I already do, except the current mapping is 1 to 1),
how would my connection of type-specific callbacks to QStandardItemModel::itemChanged be changed?
Would I then have to store a type column into the leaf nodes (so the value items will be 4 columns long), then on any itemChanged
for the whole model, I dispatch based on the type stored?