Up and running with 18346 on test desktop 2, test desktops 1 & 3 are 40% installing and 95% GTR respectively. So far so good.
I'm doing something wrong intermittently downloading from UUPdump because I'm getting "this can't run on this machine" messages from the ISO I'm creating. Maybe it's because I'm telling it to just download the Pro version on a system that's running Win
10 Home release version. I've got more to do to resolve, but WU is working just fine.
Even a Pro-only ISO ought to run on a Home Edition device. That would be one way to upgrade from Home to Pro. I am creating an ISO that way at the moment also and will do a clean install to my Insider partition to test it.