Thyme doesn't spread real fast but it does spread. Around here, we get a winter every few years that kills it, though, and I have to start over anyway.
I used an old double-tub clothes washing setup for a planter years ago, but during the real hot part of the summer the plants would wilt and die back even with 2 waterings a day. That tank of yours has enough mass that the roots don't get hot. And up off the ground like that, bet you don't get any weeds.
It is still best to be honest and truthful; to make the most of what we have; to be happy with the simple pleasures and to be cheerful and have courage when things go wrong.
Laura Ingalls Wilder