The Sagitta 900 was my third sailplane, after flying an Airtronics Olympic 650 and a Midway Models Gnome 2M during the rather long build of the Sagitta.
Beautiful sailplane, thermaled well, could come back home from a downwind run as well.
You can get the short kits and plans for the 900/600 from various sources, and FG fuselages. There is a copy of the 900 by another company.
Altezza (carolinacustomkits.com)
Like many of the 900s, I lost mine after two seasosn due to the infamous pine block/carrier tube issue that holds the very short steel wing rod.
Wings folded on the winch, despite the Lee Renaud/Al Doig "fix" that was recommeded and done during my 900 build.
Modern kevlar thread and Carbon Fiber may offer a better "fix".
I could never throw my 900 in the trash after all that work, so years later I restored it: Sagitta 900 - Return of the Living Dead - RC Groups
The details of the fix described at post #42