So what do I change to CMEast's thing?
Umm ... I guess that depends. Does the build match what you want?
How does your GM interpret Thaumaturgy? Because even if someone's Complexity matches the desired effect, I can still see some people requiring at least a few minutes set up time before you can start rolling to cast the spell. If so, then the real benefit of your Sponsored Magic is going to be the ability to cast a ritual without a physical construct.
CMEast made a very good build for a ritualist. I'd still probably substitute Diabolism for all instances of Summoning, but besides that I probably wouldn't change anything if a good ritualist is what you want.
On the other hand, if you want to lean on your Faustian Bargain a bit more, I would swap a few of those Complexity and Control bonuses, to make it easier to call on ritual spells at evocation pace.