A few things...
1. A "middle" grey card is not in the center of the optimum exposure range. At the standard rated ISO exposure, it will be about 1/2 stop below the middle, compared to the "X" crossover on a video greyscale chart.
2. When viewing dynamic range on film vs. a digital camera, the DR refers to areas where detail is visible vs. not visible. But this does not mean that the quality of detail at the extremes is the same as the quality of detail in the middle of the range. While detail in the deep shadows can be distinguished, it is very grainy, which is disguised by the compression of the detail in the characteristic curve as rendered on a print. On the highlight end of the curve, it is not so grainy, but also not so detailed either, and there could be some color shifting. So, it's best to think of the range of tones that you are capturing as about 6 to 8 stops, with everything above and below as "roll off" into shadows and highlights. This is especially true in 16mm where you are enlarging the grain of the film much more than on 35mm film.
3. When you "push" the film processing, you are gaining "exposure" in the middle by loosing detail in the shadows. So, if when you expose normally you would get 2.5 to 3 stops of detail below your grey card exposure, when pushed 1 stop you will get 1.5 to 2 stops of detail below your grey card exposure. Also when pushing, instead of 3 to 4 or 5stops of usable detail above the grey card, by over development of the negative, you will likely loose a stop there as well. So, when exposing film for push processing, instead of a perceived DR of 6 to 8 stops, it's more like 5 to 7 stops.
Personally, I feel that push processing 16mm film is a pretty harsh look. And, if you do, I would light and expose the film as if you were limited to 5 1/2 stops. 2.5 stops below the grey card and 3 stops above.