Hey, sorry for sounding like an utter **** in my previous post, I would just never complain for dropping to 7 with 80 minutes. It would feel natural and frankly that's what I was expecting.
So, you seem to have gathered a lot of interesting data. Care to share? (I totally understand if you don't want to)
Have you noticed any difference in GS behaviour regarding various stamina levels (before this season's changes)?
You didn't sound like an utter ***. You were just correcting my strange and erroneous initial reply.
Basically, what I've gathered from tracking GS shifts over the years is that there is no magic bullet.
For instance, starting at Respectable GS, there is not a specific amount of minutes played that gives a larger than a low 60's % chance of increasing to Strong, and no minutes played that gives a higher than low 20's % chance of increasing to Proficient.
Likewise, if you're at Strong GS, there is only one window of minutes played that gives you about a 50% chance to increase to 9. It's pretty tough, actually.
If you're at Proficient, you can effectively manage about a 60% chance of staying at Proficient within a fairly large range of minutes, but that is your best bet, and you still have a 40% chance of falling back to Strong.
In all three starting point cases (Res, Str, or Prof GS), playing any amount of minutes over 64 lessens the odds of a favorable GS shift on Friday morning, but not terribly drastically until you play over 72 minutes.
I haven't ran a specific case study on this latest season, or comparing various stamina levels.