X2. Induction cleaning in a GDI system is to be considered a regular maintenance item, much like an oil change.
As far as methanol, I Suppose if you sprayed a mild amount and it chipped away at the deposits gradually and the deposits were of even density and composition and ... Maybe FoMoCo can shed some light here. Ford has the reputation of having the best control over deposit formation over other mfrs, so mileage wise there is likely some leeway. Nonetheless no one wants to be the exception, so a boroscopy is a prerequisite.