The mass lesser vigor spell has a fixed range (of 20 feet),
which makes it eligible for the revised Persistent Spell feat
in Player’s Guide to Faerûn. Does that mean a 17th-level
druid could use a 9th-level spell slot to give nine creatures
fast healing 1 for 24 hours, or does the built-in limit of 25
rounds make that pointless?

Unlike Extend Spell, Persistent Spell replaces a spell’s normal
duration with a new duration of 24 hours. In this case, the
effect overrides the normal maximum duration of the spell, so it
would indeed grant nine creatures fast healing 1 for 24 hours (a
pretty reasonable effect for a 9th-level spell).

ncG1vNJzZmivp6x7prrWqKmlnF6kv6h706GpnpmUqHyxsdGsoKyslaPBbrnArKpmrpmcvLN6kHBocm9kZA%3D%3D