Personally, I am not sure it's necessary to go over it again, either here or at the other forum, because the ground is well covered and the man is not here, or there, to respond. I cannot see that it would add much worth to what is already available, just as it isn't for several others who are no longer with us.
I haven't seen any pictures of this new offering so it isn't possible to evaluate the alterations that Luis has made, and without actually holding it, it would be impossible to assess any generational issues that might be present. That said, I cannot help thinking that René is probably correct, and that it is likely to be at the G5 area, which is a point at which generational issues, such as shrinkage, can be noticeably present.
René is also correct about the proliferation of G2s that are about; in theory, it could be as high up the chain as G3, if the alterations were being made direct to a G2. It seems unlikely to me that anyone would have access to enough G1s to start sanding one of those down to make altered G2s. The only person who could answer you would be Luis, however; I suspect that the best answers about the qualities of his new offering will likely be from one of the seasoned commission painters once they have one in hand. Those guys see so many different casts that they are usually best placed to review and evaluate different casts next to one another; a Fett4Real, a Superjedi, or a Major, and so on.
I saw a Minute ESB copy, not cleaned up, when I met with John at Elstree for Steven's ear project. I do not know the generation, although I suspect it was G4+. As I stated in the ears thread, I was there to look at the ears, not the helmet, but it had clear generational issues. As we know, additional, better reference was later used to assist in concluding Steven and John's ear project.
Baruopa, what I would say in terms of going with someone else's alterations, and corrections, is this:
If you're starting with a G2 from RS, or someone else offering the same, then you're already as high up the chain with your project as you are likely to get in terms of lineage. While it's possible that someone has access to enough G1s to start tinkering with one, I think that a G2 starting point is the best any of us are ever likely to do. For what it's worth, I still cannot believe how amazing that is. To have such a close copy to the original hero helmet was once unthinkable. The fact it is even a point for discussion blows my mind. If you'd told me that any of us would have an opportunity at even a G5, which now we might pass on because much better things are available, just five years ago, then I'd scarcely have believed it. Whether it should have happened is now irrelevant; it has happened, and we are very fortunate.
Anyway, the reality is that a precast cleaned up copy is unlikely be better than G3. At that point the generational issues will be minimal, depending on the ability of the person making the copies, but will still exceed the issues with your G2. A fraction of a mm here and there, but why inherit it if you don't have to?
What you're really looking at then is convenience; do you find it more convenient and desirable to work from someone else's copy than your G2? The other issue here is that you will be working on that person's interpretation of the screen used piece. While it is known that there is better reference material of the prop in its current state than is currently widely available, the screen used reference material is likely on a similar level for most of us. Then the question is whether you think Minute, or anyone else, could do a better job than you in the restoration that you seek? There's no doubt that there are some very capable makers out there who are offering some nice helmets, but if they're working from the same reference as you, then who's to say their job will be better than yours... .
If I were in your position, I would make the alterations to the G2 helmet myself. Will you make some mistakes? Probably, but so what.
The truth is that you will probably be more aware, and more critical than anyone else is likely to be of the changes you make. Unless you make some absolute clangers then I think you will probably do just fine, and, if you asked, e.g., in a thread, then there's a whole board of people likely to offer you help and opinions.
More important than any of that; if you make the alterations yourself, and then paint it yourself, you will be invested in your prop replica in a way that you won't achieve were you to get a precleaned cast, even if you then got one of the top guys to paint it. The involvement of others in any of these steps might lead to an aesthetically more pleasing, and more accurate, result, however; if you did it yourself, then it will always be
your helmet, and that is an extremely rewarding process.
I look forward to a discussion on the new offering, but I think you should go your own way; I always do.
Peace.
Andy