Just in case anyone is curious, the dragon would "normally" be large. It's considered "huge" because of the rules at the end of the player's guide as per it being a dragon.
It also was rather lucky on the hit on Tesla (5, 5, 5, and 6 rolled on d6's for damage, and it crit).
The movement was also rather complicated, and took me forever to get right. Had it landed the grapple (it has the appropriate feats) it would have had to stop its movement much earlier, but since it missed I had to go through all the flying measurements.