I built this coil together with a friend, it took us about half a year to finish it because it was our first coil and we had no experience with tesla coils.
But now it works very well and it produces long streamers :)
you can follow our youtube channel if you want.
In this Video the coil plays the "Force"-Theme from the new starwars movie
https://www.youtube.com/watch?v=KtqouUNPkOc

Our next goal is to build two big twin DRSSTCs :)