Propsmith,
Thanks! That's very generous of you to say.
A while back, Thomas posted this of the Elstree vs. one of the tour ROTJ.
Structurally, the Elstree has a lot going for it.
Here is a picture of one of the two Jeff ROTJ masters:
And here is the other one, formerly GINO's.
As you can see from all the above, the closer you get to an LFL mold, the more detail you have. However, it's still possible to oversharpen detail when you go the bondo and sandpaper route. That being said, the amount of paint you put on there also determines how much the sharpness gets rebated. Some people see the exhibit LFL ROTJ and don't really take the amount of paint into account.
I've seen photos of an unpainted Elstree casting, and the detail is sharp. If you go very thin with the paint on an Elstree, you can get a nice sharp effect. Also, if your mask lines are done very cleanly, they will contribute to a sharp appearance. However, the sharpness of the lines can be determined by how many layers of paint you shoot it with. I'm sure in his assessment that some forget about the role of paint thickness in the final appearance of details.
So there should be good detail (as opposed to the soft detail of a Don Post Deluxe and a lot of over-painted fanmades).
It's quite possible that the master used for the limited run of 10 Elstree-derived castings was made that sharp.
Here is an LFL prop - one of the pulls from an LFL mold. That particular generation of pulls was used to engineer the ROTS Vader but this one is an unaltered pull (i.e. no symmetry).
It's sharper in some respects than what we're commonly used to. It may not be quite as sharp as the Elstree, but a lovely pull nonetheless! It's not identical to the Jeff ROTJ Masters in some of its features either. So hopefully this will provide some food for thought. My favorite thing to do is to approximate the screen captures provided the screen caps were analyzed correctly.