[Sombre]

Even if you do add an entirely new spell and define it by number, your mod will have trouble when used with other mods adding spells I believe.

It seemed to me that it's complicated and fiddly to the point of being useless, so I stuck with using #onebattlespell with existing spells.

However one idea put forward was that you make a copy of an existing spell, then you alter the one you copied to be your new spell - that way it gets a fixed number. The copy you made works just like the old one did, the only difference being the indies don't use it, I think.