[Twan]

The maximum number of rounds for a spell duration is 9.

#effect mod command
x = battle spell
100x to 900x = "cloud" of spell x with one to nine rounds duration
1000x = ritual version of spell x

Then the number of effects of vanilla MoD is the number of rounds x mage level (with unlimited number of rounds, but usually opponent is routed at some point)

My number of effect for 9 rounds is 9 x ((3 x mage level) + 2) = 27 x mage level + 18.

So number of effects of my version is about the same as a 30 rounds long old MoD spell, it's just concentrated in a shorter duration.

A 30 or 40 rounds MoD, even with just one effect / round, would anyway be far more powerful because the bugged way this kind of spell works make its duration = minimum battle duration if the caster retreats (and in a 40 rounds long fight some spells like Wrathfull Skies or fatigue BE can be devastating).

I find 9 rounds a good medium (between making MoD an instant or keeping it as it was), allowing to use MoD to make battles longer but not too much, so even the combo with other BE can be allowed.