You are right that one

curve determines the other and vice versa. And to solve the acceleration time problem, I started with F=ma hence the torque curve. Sure, someone else could have used d(Energy)/dt=Power, solved for Energy, and took square-root for Velocity. Even more so, a physics major could do the general Hamiltonian approach. But math and physics being consistent and all, that someone else would get the same solution as mine. If he started with the power function P, he'd find out that somewhere he had to divide it by x (rpm), thereby reducing it to torque only.

Without doing the actual calculations (yesterday), I had always been misled to think that it was actually torque * rpm that gave acceleration. This came as a revelation after I took the time to think about it. Just wanted to share and hopefully clear some mistaken notions.