I do both short and long lockouts, and they are a favourite exercise.
Long lockouts, from my traditional sticking point; about a 3-board, are at about 60% of my raw max. These are tricky as I try to follow my shirted groove, without a shirt...
Short lockouts are only about 3" of movement, and I aim for about 110% of my shirted max. If I shorten the stroke up I can get some silly weights to move, but didn't find as much training benefit.
I don't do the eccentric on the shorts; basically dropping the bar. I bought a cheap bar to beat up with these.
A variation is to narrow your grip up a bit and realy focus on the triceps.
Another good one is to double loop a band over the bar, and do lockouts against monster band tension.