26.25 seems like the best fit to me too. It doesn't perfectly fit all the test data, namely a 165 speed firestarter/commando should be able to move forward 5 hexes and forward/diagonal 2 hexes, since that would total 163.93 meters, but they can't.Yea, I hit those same inconsistencies in my initial testing. The number 26.25 kept coming up when I did the math for most units dots/distance in the files. It seems it costs 26.25 to move a hex, but each hex is only actually 24 apart, given you set a weapon to 100/200 ranges as a "Laser Range Finder" and turn all others off.
On the other hand, if you adjust the dot distance enough for the firefighter/commando to make sense, then it doesn't make sense that a locust can walk 8 dots in a straight line. So 26.25 is about as close as it can get to matching my test data. It's mathematically impossible to fit all the test data to a single dot-distance without making assumptions about the test data being wrong, such as uneven terrain, etc.