I’d like to support the beta testing, but I noted that projects will open in the most recently installed version. I’ll need to have my projects open by default in 1.9, as I have quite a few projects and shortcuts set up to launch them. If I installed the 3.0 beta, then ran the 1.9 installer again, would the projects then open by default in 1.9?
Yes. A reinstall of 1.9 will make it the default again.
You can also just change the default app by file type in Windows settings. No reinstall, easy peasy.