[3.5]Greater Produce Flame (PEACH)

[Temotei]

This is correct, any ideas on how to clarify the wording?

You could copy produce flame's text.

"...dealing fire damage equal to 1d6 per minute remaining + 1 point per caster level (maximum +10)."

It's simple, basically updates produce flame's premise, and functions just as you want it to.