"
by half-way down the runway"...............runway lengths vary from less than 2,000' to in excess of 12,000', with varying types of surfaces - grass (long/short), gravel, sand, sealed - gradients, and elevations.
The 80/100 knot calls made by the "big boys' ", are NOT for the reason you have stated above.
If you
REALLY feel the necessity to twiggle the toggle, then a better understanding and use of the P charts applicable to the aircraft type, and take-off airport(s) on your day of operation, will go a long way to making you a safer pilot than your current practice.
(Don't forget - blue above, green below).