@Pardus Tricky.
Stack two tabs and tile vertically would work for many use-cases, but some of us use a portrait monitor.
What happens with Stack three and tile? Vertically, or to grid?
More than three tabs would presumably tile to grid?
If you want to tile only some domains on stacking tabs, that means maintaining a list of domains, which is barely practical.
You could make a command chain to stack and tile the selected tabs, and add that to the Tab Context menu, but then you can choose only one style of tiling, or you need multiple command chains.