Handful of questions!

[Elethiomel]

Even with 85% to hit with the touch AC, SR 22 means the 10th level wizard with Greater Spell Penetration (+4, so he needs to roll 8 or more) will only succeed in both hitting and penetrating the SR (85% * 65%) = 55.25% chance. Add in an entropic shield (20% miss chance), and it drops to
44.2%.

If you're still talking orb spells, they're not subject to SR.

 

[green slime]

If you're still talking orb spells, they're not subject to SR.

Know I remember that's one of the reasons why I removed the orb spells from our game, that and the wonky school.