Use ball valves.
OK, now that that's out of the way...
I Googled about installing them upside down like in a basement. Saw pros & cons. Mostly about it promotes sediment collection messing up the operation. The ones I'm using are 1/2" & 3/4", one hot and one cold. There are no flow direction arrows on them.
What's the feel from you folks on upside down installation from actual experience?
Red...