@ Lee - I believe that the 'workprint' version is a fan edit, but I haven't seen it myself. However, if you search YouTube for 'Prometheus Workprint Edition' you will come across a trailer for it which features some of the extra scenes in it. Until I get around to doing my own ideal cuts of Prometheus and Alien Covenant, my own current go-to is the excellent 'Prometheus Special Edition' fan edit by Agent 9
(YouTube also has a trailer for that)
Like that version, I'd definately get rid of the official 'Engineer' prologue to keep their reveal a mystery for much later in the movie, and replace it with the younger Weyland TED sequence instead, no matter what. And there's plenty of trimming i'd like to do to Alien Covenant too.

As I previously described, I no longer regard Ridley's 'Prometheus' movies as being part of the ALIEN/ALIENS storyline setting whatsover...and it's clear that from his comments that a lot of his ideas make little sense regarding this franchise now. Having said that, I'm still interested to see what he has David doing next, but I'll look on this storyline as being a totally separate, 'alternative universe' reinterpretation to the original Dan 'O Bannon/Ronald Shusett Alien storyline instead.
On first hearing of Ridley's new proposed take on his original 'Spacejockey' as being a 'spacesuit' instead of a huge skeleton, I remember being nervous that it would end up being a human
(possibly Shaw) that would end up inside it by the end of 'Prometheus', rather than some large extra-terrestrial being of some sort. I was wrong about that, but I wonder if it will now end up being the man-made David who will pilot that particular 'derelict' by the end of these new movies? We've already seen David put on the 'chair' during 'The Crossing' clip, after all...but on the other hand, he's NOT seen wearing the supposed 'helmet' section in that,whereas it WAS being worn on 'whoever' was in the 'suit' in Ridley's way of looking at his original movie.
Either way, it won't matter to me...as I will keep it separate from the original two movies, and look on the ALIEN/ALIENS 'Spacejockey' and 'Xenomorph' storyline as showing truly 'alien' Lovecraftian nightmares, thankyou very much.