fart-
The 35 feet is important in so far as the obstacle clearance in the t/o flight path is concerned. You must miss all obstacles by the net climb gadient (this is different depending on low many engines you start with) plus 35 feet. So at 35 feet at the start of the t/o, you are just starting your obstacle clearance path.
stardust-
All other conditions the same, i.e. rudder throw and square footage, thrust, etc., the Vmcg WILL vary with the fuselage length. Your carrier (for whatever reason) may not choose to use any modification of Vmcg for x-wind on those models. A longer fuselage has a greater lever, so the Vmcg will be lower.
The width of the runway has nothing to do with the value. The only concern is how close you can keep it to centerline, not how far from the edge.
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