PEI, you're worried about getting everything down to the n-th degree and it's just not going to happen. In the big picture (and in the real world) when you're within 5 knots of V1 you might as well be at V1 as far as decision making is concerned (since we are not lowering V1, just the V1 call). Above all else, though, don't forget to fly the aircraft, if you need to reduce power and/or stop above V1 because it can't be controlled then do so.
As you mentioned, there are a lot of variables in aviation, but contrary to what you said, not all of them can be known/accounted for (there are simply too many).
Your last statement is rather confusing though. A greater level of understanding and learning is achieved from perceptions (experience) and grouping those perceptions into insights (understanding). Too often pilots become mired and obsessed with minor and unimportant aspects of an issue. Reminds me of the phrase "losing sight of the forest but finding the trees".
There is a Boeing training video which goes into great detail of what all the V speeds are and how they effect you, as well as how being above/below them effect the aircraft.
Finally, while Vmcg is a concern as far as flying the aircraft, short of the engine falling off the wing or simply disintegrating it will continue to produce some power for several seconds after the point of "failure" as it spools down. In the case of an engine fire, full (or nearly so) power. We can throw what ifs around all day to get this thing down to the n-th degree, but still, at the end of that day, 5 knots early (for the call) is not a big deal.
Last edited by aviatorhi; 17th Dec 2011 at 05:42.
Reason: spelling