If I remember correctly, wasn't this Eidolon supposed to be FAR bigger than even the hydrolyst, or was the scale being skewed? If what I remember was right, then I'm extremely underwhelmed atleast on the size, I was expecting a behemoth of a boss that would take up so much space and we would need to use our archwings to take them down.
About the 1000 ducats being too much, it's really not. I remember completing the quest for the Paracesis and going to check how many ducats i had and realized I only had 60 ductas, so I decided to dedicate a few hours to farming fissure survivals and defenses. Lo and behold I was done within 2 hours of starting my farm. While I did get lucky and get some rarer parts, a majority of my ducats came from 15 ducat sells. Don't say something takes too long if you haven't even bothered trying it