A tale of two installs.
I had problems with the first install of an iso via calamares 3.1. As for years is set up the usb key via "dd". It borked - failed after hitting enter on the "install via usb" line (different distro). It kept complaining about unable to get the squashfs from sdb. I tried, I tried, md5 would not list on the usb key on a stable machine. However redoing the usb key via "cp iso /dev/sdx" and "sync" worked. I did not try to set it up on a lvm base. The standard easy install put everything (except swap) in one partition. All in all pretty easy, but not set up the way I would like.
And then I tried with the 4.7 Sparky. The other distro had a "Calamares" icon on the upper left. Sparky had no icon, but the menu with standard install went to a calamares install. And it went smooth. If anyone has any success at installing onto a pre-existing lvm partition system, please mention it. I will try that later this week.
The moral, Calamares looks and performs quite similarly for different distros. And I believe I will transition away from "dd if=blah.iso of=/dev/sdX bs=512k" to the "cp" method. Can't wait until it handles lvm