Yeah, this would be really great. There’s already a bug tracking this at https://github.com/online-go/online-go.com/issues/2551. I know how to implement this and I’ve been trying to find time but I just haven’t gotten to it 
It needs a backend patch in addition to a frontend patch. The plan I have is:
- Add a setting to the group for the default correspondence settings. Make the default the same as the current default for ladder games. (This needs a backend patch as well as a frontend patch.)
- Use this setting for new ladder games in the group. (Actually, this should happen “for free” in the backend patch above.)
- DO NOT use this setting for new tournaments, since the current default for new tournaments is a different default. (Nothing to do here; just a note NOT to implement a frontend patch analogous to the ones for rules/handicaps.)
I didn’t implement right away when I implemented the others because I wasn’t sure if that was the right plan… another option would be to also make the default ladder correspondence settings the same as the default new tournament correspondence settings (in which case, which default should win?) and then you could use the group setting for new tournaments as well… but at this point I’ve dithered too long and I’d have been better to just go ahead with a plan that works!
Please ping me and/or the issue in September-ish, when I’ll be back from a break, and I hope I can get it done.