I sold my 600 hour TSC1 for 16.5k 2 years ago. It was in good shape, but not showroom by any means. I've been seeing TSC3 hulls with ZO going around the 24-28 mark (and bought one there too), so that gives you an idea of the room for a TSC1 with ZO.
While I personally like the TSC1 hull better than the TSC3, the fact that it is a 'non-factory' setup was a deal breaker for me. I have no interest in that type of setup. Support, resale, parts, all become more difficult.