TR
Yes, normal landing weight was 635,850 (yes, a common evaluator question) and there was only a sink rate limit on landing at max TOGW. As noted, the ACN was rather low for its mass. At 635,000, Vref would be about 135 KIAS and dry distance, using max anti-skid, about 4700 feet, around 1600 of that "flare distance" from 50 feet over the fence. I landed at about that weight at RMS once, used heavy braking but not max, and cleared at about 5000 feet from the approach end. No, I won't tell you why I tested the charts. Another time, on ice, RCR of 6, computed distance at about 560,000 was 5000 feet. Low and behold, stopped on a 7000 foot runway abeam the 2000 remaining signboard.
Hope it helps.
Add the number of thousands of pounds to 75 and that was the approximate Vref. IE, 500,000 pound plane would have a Vref of 125 KIAS. 10 Knots less would be a rough V2.