You can use thaumaturgy to give yourself aspects, three shifts for a fragile aspect more shifts to get the fragile aspect to stick around longer. So is it possible to give yourself a lot of fragile aspects that enhance thaumaturgy then use your free tags to create spells with a large complexity and safely power them up very quickly?
Not only is it allowed, it's encouraged by the rules as a method of involving the entire group in casting. (YS272 Using Help) It's also featured in the fiction and shown in the thaumaturgy spells pulled from the fiction. (YS301 Sells' Heart Exploding spell)