Same input... I've had a couple of Hill TD's and never took them apart. I now have a couple of hinge TD flatbows, and they live apart in a roll up case with a dozen arrows... put together only at the range. They're just so easy to assemble and disassemble. The sleeve system, while effective, is IMHO messy and stiff to work.
If you really draw 28", get the 68", if you're a bit short of that, you won't notice the difference between 66" and 68", but at 28" to 29", you very well may. There is variation between bows, though I will say that the several Cheetah's I've had were among the smoothest Hills.