It is possible to get a dupe Madara. After you pull your first SR it will reset the counter meaning you will have to pull another 800-1100 seal scrolls. I got my SR at 960 pulls.

Thank you. I seem to have less luck because after 1020 pulls and getting every rare still no sign of Kurama/Madara...

Should get one of them hopefully in 80 or less scrolls, but I think at 1200 or 1250 it will for sure drop. I think the average is 1050-1100, so hopefully you get one of them soon.

nope, is granted you won't get a dupe.

Nope, if you get Madara your next one will be Kurama Naruto. And it will take another 1000 or so seal scrolls

Hi! Just to avoid any confusion. The Super Rare pulled in Great Ninja War Treasure will have a 50% chance of either Madara [Founder of Konoha] or Naruto [Kurama mode]. This chance is not affected by getting one of the Super Rares in events. This means that if you get Madara [Founder of Konoha] fragments from events and you recruited the ninja, your chance on your first Super Rare in Great Ninja War Treasure does not change(Still 50% chance of either Madara [Founder of Konoha] or Naruto [Kurama Mode].

However, if you obtained one of the two Super Rares in Great Ninja War Treasure, the next Super Rare you pull from the GNW Treasure will be the ninja you did not obtain the last time. This means, if you pulled Madara [Founder of Konoha] as Super Rare, the next time you get Super Rare will be Naruto [Kurama mode] and vice versa.

In regards to your second question. based on player data, it is hypothesized that the threshold to obtain a Super Rare is 900-1200 (around but could be more or less); regardless if you pulled a Super Rare before or not. However, there is always a very small chance to pull a Super Rare on a draw, but it is very rare.

Note: There is no guaranteed second Super Rare for 60 draws after pulling the first Super Rare.