The most proeminent question I try to answer concerns a changing that occurs during the ninth year (in the interrupted chronology I saw here on the forum). It seems to happen precisely during the FF miniserie in the Negative Zone.
I see something is happening with colors at that moment. And I think Glynis Wein makes a difference here, in comparision with the previous episodes of FF. (I have been told that Glynis Wein was colorist on the Galactus Epic unfinished serie, which was watercolored I think. But I have no certainty about that, because I do not own this story and only know it from images found on the Internet).
But what strikes me concerns the caracteristics of the line or of the stroke in the inking.
Something changes at that time. I call it "the alpha-flight line", because it concerns the  all inking of the saga, when Bob Wiacek doesn't do the inking.
it can easily be perceived in the 17th episode, when Logan comes to visit Heather at the hospital, because the remembrance introduces pages taken from Xmen which were inked by Terry Austin. the gap between the two styles of inking his easily catchable.

So I wonder if John Byrne has changed one of his tool at that time, for example going from brush to pen, or from rapidograph to isograph, or such tecnhical change in his daily routine ; or if it is due to another aspect of his work that I don't guess yet.

I will be glad for any tips on that topics, including about other periods where a major change can be observed in John Byrne's art.

Thank you all.

Then Alpha Flight started taking more time and he decided to have inkers to share the load (Wiacek and Ordway and some others from time to time)...

It was the thing Athanasios referenced -- JB was working at 'twice-up' and the standard was to work on 11" x 17" bristol board reducing to 6.625" on the printed page, which is a reduction of 1 and 3/4.

That increased reduction should, in theory, have made JB's work even more razor sharp when reduced, but for whatever reason -- presumably to do with the printers not being used to working with that -- it came out with details kind of blended into one mass in places.

For example look at this crop and compare between the original art and the printed:

Alpha Flight #1 has a cover date of August 1983, so this is just about the same time as Alpha Flight. Perhaps you refer to some inking change later in the year -- if you have any samples to illustrate the stylistic change that you are referring to it might help.