Hey, You will get IITD and IITB for sure. I am not very sure about IISc. because last year IISc cut off was around 51 rank
Also, if you want to do coursework and not Research, then I prefer IITB over IISc, but I do not know why are toppers preferring IISc over IITB. IITB has better teachers. This is my personal opinion, You should contact other IISc and IITB students and take their point of view before making a choice.