Experience with Paragrafix 1/537 Refit jigs?

[Odysseus]

Hello group. I was looking at Paragrafix's photoetch set for the 1/537 Refit and see that it has alignment jigs in the set for the warp pylons and neck-to-saucer fitment. Anyone had any experience with these? They don't look easy to use, but could be helpful with some patience.

Thanks.