The flute is normally in the middle of the stick, I guess simply to protect it from the wear and tear that would normally occur at the bottom end. That means you would either have to make it in separable sections for an open bottom end, or add an extra hole for the bottom note. See for instance the Sweetheart ones
I was always under the impression that Dizi
style flutes (and Kill Bill flutes, for that matter) use the extra lenght of bamboo at the top end instead of a cork stopper or bamboo node, to create the required counterpressure on that end. Although I cannot find any online information that confirms this, I did manage to play a little scale one one of these flutes in a shop someday, and it did not have any kind of stopper fitted. (Nor a Dizi membrane, by the way. I was quite puzzled that it all worked in spite of both these facts, but that's how I learned that it could be done.)
As for the Flutomat, just try to enter the values of any existing flute, just to see how much they can differ from the Flutomat's indications. Especially the mouth hole placement seems off to me, which is why you might want to make a few attempts, just to get a feel of it. (I have once made a calculator in Java which uses some of the alternative calculations mentioned a.o. in the Flutomat source code, a few constants of my own, and some extra maths for the different tube diameters that occur in a conical flute. But the deal remains largely the same: for each of my existing flutes, I have to use different constants in order to come close to the actual numbers.)
And of course, always start out too low (smaller holes/ longer pipe end than indicated), so that you can still tune it up. (The Flutomat might be a tad confusing there, because it starts the measurements at the bottom end.) And start tuning the lowest note first.