I have no idea why it would be necessary to use a reverse-log pot for the Dist+. Unless there is some very specific degree of distortion you need to dial in, there is absolutely nothing gained by using one taper over another. The circuit certainly does not need any particular taper to function.
All that pot tapers do is provide a particular degree of resistance change per unit of rotation. In some instances, if the audible change is such that the ear detects it as nonlinear, or if the user needs to have a certain amount of "rotation arc" reserved for a particular range of change that they want to be picky about, then taper can become important. But other than that taper is less magical than most think it is.
The few cases where pot taper is truely important seem to be:
1) Anything where you are controlling the volume. Log taper provides smoother volume changes because of how the ear works.
2) Anything where there is a defined "middle", such as balance controls, or EQ cut/boost controls, where it is important that the midpoint of rotation (or sliding) be very close to half the max resistance.
3) Anything where you continuously move the pot with your foot, such as a wah or expression pedal. In these instances, the pot taper is actually compensating for the degree to which foot movements of different angles can be articulated. You can provide fine gradations of movement when pushing forward with the ball of your foot, but only much coarser movements when rocking back on your heel.