It certainly shows, that the size of an individual is enough for the Ignem light spell IbTtL.
If you also wish to see, how T: Ind is sufficient for spells controlling a Form around an object of another Form for some time, see e.g.:
ArM5 p.124 ReAq 5 (R: Touch, D: Sun, T: Ind) Cloak of the Duck's Feathers
and many other Rego spells in the core book.
It does not appear to be a problem, that in CotDF the water around the object changes over the time of the spell effect.
If you wish to elsewhere continue the discussion started by @TimOB in your thread here, feel free to start that different topic. I so far just answer to questions and objections posed here.