Originally Posted by Bill Kapaun

"...I am thinking that an 11 teeth might be more useful for me in increasing speed on the flats without going on the bigger front ring. Am I right on this assumption?"

Then you are cross chaining which isn't recommended. The Big Ring is for the flats!
Do you spin put with the 52-12 combo? If not, going to 11 doesn't really do any good.

"...I barely use the 25 cog."
Which means you still use it!
My theory is to always have 1 gear lower than you would expect to use for 99% of your riding. It's that 1% that bites you.