Congrats! That's beautiful. I'm still kicking myself for not jumping on one of those 960s when they were coming into the country as surplus. A lot of Astras have an adjustment ring under the grips where you can adjust the trigger weight. Interesting design.
Absolutely no clue if this is true, and not suggesting you try it, but when studying the 960, I remember reading that the 960 was designed as a .357. It was sold in .38 configuration because some police departments didn't want to use .357s. However, the basic gun in many (if not all) cases is still the .357, and just is stamped .38 spl. Supposedly, .357s fit in the cylinder no problem because the only difference was the caliber stamping. Hopefully, someone who knows more than I will chime in.
As far as Astras, I own a .44 Terminator in almost mint condition. Have the box and everything.