Temp for "done to well-done" beef?

First of all, let me say that I like my steaks pretty rare, and most of the time if someone asked me to cook a well-done steak, I would throw a hamburger on the grill and burn it to a crisp for them. I'm planning on cooking a couple of flatirons tonight, and my mother-in-law musn't see a hint of pink in hers.

Thus, what is the minimum internal temp that will get rid of all pink? If possible, I'm hoping to cook it until there is no pink without turning it into a dried up piece of shoe leather. This will begin the weaning process from burnt food toward medium and then on to medium rare!

I'll be using the standard TRex method and hoping this will allow me to maintain some level of moisture in the meat.

So, has anybody ever measured the internal temp of an overcooked, partially burned flatiron?

Meat