Jeepers. I don't know where to start. Baron 2PG got close- but the emphasis needs to be on Gross Weight at time of departure. If you are above your V1 speed, but still within a few feet of the runway, you have a choice: FENCE, or treat is as an inflight emergency. If you are substantially below Vyse at V1, you just fried everybody aboard. Please don't do that. you're not going anyplace up.
The real problem, is if you are sufficiently loaded so that you are still on the ground gear are down and your V1 speed has passed, well you just screwed youself.
It is a matter of discipline to alter (reduce) you loading so that V1 is both above Vyse, so that you stop, OR you can treat it as an inflight emergency. Or you get the treat of the week- the tree and the fire.
If you don't do that, you're not thinking right. Even 200 undergross changes the numbers required Dramatically. In my a/c at gross, the 5500 ft accel to Vy and stop (V1=Vy), occurs at about a 4,200 field length when 200 undergross. 300 undergross changes it to under 3800 (V1=Vy). The SE climb gradient gets a lot better, and of course is published. Adjustments made of course for temperature and wind, and baro!
Then you have the matter of clearway gradient. New apartments 50 feet high have been erected in my departure path. The option to go, when V1 = Vyse at my home port (about 200 under, most conditions) is now gone. So now my depatures from the home field depend almost entirely on V1 vs Vy and the option is to STOP in the 4000 I have. So now I'm more comfortable wtih 250 under gross, and at that terrible moment, I planning to STOP.
"Kick the tares and light the fares, she'll do 'er" is not acceptable in the cautious operation of a light twin.