Dont confuse SPEEDS with THRUST settings.This discussion is about TAKE OFF speeds.Okay here is a problem for you.Due to whatever reason you must divert to XXXX.You have no runway analysis, your OPS department cant be contacted, but you must depart NOW.Where do you get your speeds from? FCOM? QRH? The runway is 13000 feet long, so performance most likely isnt an issue as the ocean is off the runway end, no obstacles.This has happened to me several times in a big jet.