Couple of points about takeoff procedures.

Firstly it is very dependent on the weight of the aircraft. For the same type with minimal fuel and payload they can get off in half the time of one up to gross weight.

Nowadays most takeoffs are done by a calculation of how little thrust is required to get off, this has a positive effect on noise and fuel cost and a very positive effect on engine maintenance cost if it is rarely run up to high power. The general aim is to get off in about 75% of the available runway. So if you have a longer runway you don't advance the throttles so much. The calculation required will also give speed and seconds at V1, the go/no go decision point in takeoff, so if things aren't working out there is space to pull up.

Should have no impact on safety although there is expectation that the recent cargo 747 overrun on takeoff accident at Halifax, Nova Scotia (not yet fully reported) was in part due to a miscalculation of the power required.

A current issue with certain GE-powered 777s requires them to make full power takeoffs for the time being. If it's a light load the performance is spectacular !

Just as a rule of thumb, expect about 30 seconds roll in a standard jet. The busiest runways manage a dispatch rate of about 1 a minute, and the preceding aircraft is always well clear before the next starts.

Regarding a "rolling start" or "spool up against the brakes", it is a common procedure to require the latter for the first departure an aircraft makes of the day, just as an additional test that all is working to spec after standing overnight