i dont think x speed will automatically calculate out to clearing x gap.
thats like saying going 100 km/h i would clear a 100km/h gap which first of all doesn't exist and secondly even if it was 100km gap you wouldnt make it adn you would eat sheat.
It would be more like x speedn clearing y gap... grade 6 math.
Then if you want to get fancy you can calculate gravity, air resistance, friction of snow, what the effect of gravity is on you as you get higher, angle of power, energy required, snow density, effect of albedo of snow, trajectory, min and max of jump, graph your jump, add any variables such as trees in your way, calculate the probability of an eagle hitting you while in the air, distractions (like manbearpig), and probability of your mind not being able to handle all of this while you are in the air (but i can do that for you its 100%), probability of you failing and eathing shit (also close to 100%), the speed of light while you are in the air, time dilation which occurs while you are moving, how long the landing needs to be taking into acoutn length contraction, and finally how much you will need to eat to be able to build and test the jump in order to have enough energy, and i forgot your mass at different points of the jump.
In short go to a ski hill where they may suck but at least they are already there.