Hmm. You're right; you can't redirect actual Thaumaturgy - only evocation.
On the other hand, you still can cast 5-6 shift Thaumaturgy rituals that apply one aspect for a day and take the minimum time (a couple of minutes) to cast because they are within your (modified) Lore. Imagine a wizard spending two hours preparing each morning, casting, say, sixty of them.
When the battle comes, he takes out his hand crossbow, whose bolts have been "enchanted" with six aspects each; "trueshot", "magic", "accurate", "bane", "seeking", "slaying". You shoot the Weapon 2 bolt with +4 weapon skill and tag its aspects for a +12 to your weapon roll for a whopping total of +16.
If you're a sufficiently powerful enchanter (i.e. you got high Lore, specialization and foci to get a higher effective Lore), you could make the aspects last for weeks with minimum casting time. And you could stack up on bolts of slaying.