Oh wow, what a senior moment
Yep, you're right, Double D.
For an 8% difference, you want 235/55-17
rpm's go from 4800 to 4411
Best tire choices = Pirelli PZero Nero M+S*, Kumho ECSTA SPT
For a 7% difference, you want 225/55-17
rpm's go from 4800 to 4482
Best tire choices = Bridgestone Turanza LS-V*, Kumho ECSTA ASX
* -- Preferred because they are rated as quieter tires, which is important for extended high-speed commuting. The wind noise and road noise/drone of the tires can be fatiguing and bothersome over time. At least you'll have the road noise covered. Not to mention, they also top all other category ratings and are a good price as well.