The way I am going to do it with my shadowcraft mage is with Signature Spell(Silent Image). I don't think you got the feat(s) to spare but the fun with Signature Spell + Shadowcraft mage is that you can spontaneous cast all "imitated spells" and prepare your spell slots with normal spells.

But unless your DM is exploits weaknesses don't worry to much about fully SR-resistant encounters and just get some wands/scrolls/runestaff/knowstone for the case it does happen.