Loading the kayak to the top of the TC is not what I'm worried about, it would be lowering it - by yourself.
Currently (to unload) I grip the kayak stern and simply walk it back and lower to the ground (safety line in place), but on a TC, I would be lowering it down while standing on top of the TC; like swan diving it into the ground - one will get to a point where most of the boat is below and hanging off the TC while I have little more than the bow to grip. There will be a point when the kayak will have the cantilever advantage against me.
It's the graceful landing I'm thinking is problematic.