PTH;
Thanks, re FOQA.
Are you referring to the height of the actual white runway light fixture? Would a difference of even a foot make a difference in judged flare height? I don't think so not perhaps because of the tiny distance difference but because the question assumes that there is a background (the runway surface) against which one sees the light - If that is the case, one can see the runway. If it is that dark and rainy, the surface of the runway will be difficult to see and therefore judge; whether the lights are one foot, six inches or variations on the theme, is not going to materially affect the flare height. In fact, if it's that wet and/or flooded, why flare at all - why not just a slight touch back at, say, ten feet on the RA which the non-flying pilot can call (or the 320 calls for one)? We all know that a touchdown on a wet runway can (and should) be much firmer than a dry one and not be a bone-jarring arrival.
Just a thought.