Larian Studios Forums Divine Divinity (English) General Recommended second mage damage spell

I have a level 19 mage. Just got to steel scorpions, which of course are immune to Meteorstrike.

I see three main choices for how to deal with them:

1. Use the Spider statuette and pass them without killing them.
2. The 'Hellspikes' spell.
3. The spell with metal discs.

In testing, I put two points into Hellspikes for one test and two points into the discs for another test.

The discs seemed to kill it much faster (in fact I had to put more points into Hellspikes to kill it).

What would people suggest, to use the skill points well, for the 'next big spell' since apparently Meterostrike needs to be supplemented?

Is there much use in the other damage spells using elements, or is better instead to just add the physical damage spell(s) above?