I don't think it would work well enough to justify the expense. In general longer tanks produce bigger waves, wide and deep tanks shorter waves. For wider tanks the extensions provide a bigger boost, on deep tanks, too much wave energy is lost and they just don't work that well. I really wouldn't recommend the wavebox for a tank more than 36" deep. 60" deep will be extremely expensive and very difficult to light and I might rethink your plan a bit and maybe just place a decorative scene or create a shoreline effect, you could have the tall tank but only fill it 36" or so, though working on it would be very difficult and then create tall rock mounds that go above the surface 6-12" and possibly have some mangroves. This way the tank could be built to withstand the weight of 36" of water and be much thinner but you would have to be careful to never overfill it.
