LOL!
Once you have Time Stop + Improved Alacrity, however, Dragon should pose no threat at all.
Just use AoE spells, which will bypass his Spell Turning.
Since Saladrex has no Magical Damage resistance whatsoever, Skull Traps are ideal here. Just cast Time Stop, follow with Improved Alacrity, release a Spell Trigger with x2 Lower Resistance and 1 Greater Malison. Continue by casting as much Skull Traps as you can.
Two important things to note: First, release the Spell Trigger when you're close to the Dragon, then take a few steps back and go on a Skull Traps frenzy. This is to ensure that the Trigger's spells will take effect
before the Skull Traps. Second, be sure to take another step back just before time flows again, unless you wanna share Saladrex's pain, too.