Qualifying the JEE ST Cutoff wont just lead you to a Seat at IIT. Securing an ST Rank between 900-1000, you have fair chances of securing IIT. For ST Rank 900-1000, you need to target a CRL anywhere above 25k. For a 25k CRL, considering the moderate to tough paper nowadays, you must target atleast 70 on a Total between 360-372. Incase you target higher around 90-100, would be better and lead to excellent prospects during JoSAA Counselling for IIT.

For more information about JEE Advanced Cutoff do follow the link below

https://engineering.careers360.com/articles/jee-advanced-rank-list

Dear Aspirant , for JEE advanced

as per analysis of jee advanced 2020

nearly 8.75% of total marks considering paper 1 & 2    and 2.5% marks in each subject ,might help in clearing cutoff for ST category (this may or may not be precise due to change in pattern and other trends every year.)

You can find more detailed analysis of previous years of jee advanced  here :

https://engineering.careers360.com/articles/jee-advanced-rank-list

Also this might help -

https://engineering.careers360.com/articles/how-crack-jee-advanced-2021

ALL THE BEST !