I hadn't decided on that - does it make a difference?
Currently I have in mind to try the one-click and if it doesn't work right for me, then do a manual install.
I'm inclined to make a subdomain for it, but still wondering about putting in the subdomain's root or its own directory. Maybe as there doesn't seem to be an 'advanced' one-click I won't have a choice anyway, unless I do the manual install.
It's not urgent so I guess I'll make a subdomain and try a few things out.