Subcircuits can now be used within the TinyCAD interface using the "mason_subcircuit" library.  The only (known) limitation is that the PADS ASCII output feature cannot yet be combined with a run using subcircuits.  PADS outputs using single or multiple pages in TinyCAD still works the same, and subcircuit usage still works the same in the Windows and Linux command line modes.

I don't use subcircuits much, I tend to use multiple pages in TinyCAD, or generate new dynamic components using existing circuits (there's a flag for that).