Have you tested if 4 Don Quixote engines give more speed than 3? Or than fewer, larger ones? I'm not sure if it is reasonable to make it so big. Also, how did you stretch the first row slightly further from main zooid?
I've yet to do further testing with said engines and how the number of engines affect speed, although that is on my to-do list.
As for the first row being ever-so-slightly further, that is the result of the soft-body handler glitching a little (normally extended connections like that are not possible, but would you know it, the building method for the engines can result in said glitch occurring) due to the symmetry of the creature (the devs did state that the handler hates symmetry).
After a bit of testing, I've come to the conclusion that yes, the above creature does need that many engines. Even though its speed matches (or is slightly slower) than a smaller creature with only 2 small engines (pictured below), the greater number of pusher-type Eater zooids means that the engines are able to function for a much longer period of time (since each engine adds more energy regeneration with each Eater). The creature below can also achieve speeds equal-to-or-higher-than the above creature, but it can only do so for a much shorter period of time.
As such, it is actually recommended to build larger creatures if one wants to use the Don Quixotting method of movement, due to energy constraints and the fact that engine size/count negligibly affects the speed of the creature while Don Quixotting.
Also, as you can see, the slightly-larger-than-normal gap between zooids is present here as well. As I've said before, it emerges due to the building method for the engines seemingly screwing up the soft body handler so as to accommodate the pusher-type Eater zooids (which are slightly larger than structure zooids) in-between the structure zooids.