Jitesh ji, in Tatkal, where only 25% is refunded once booked, I will not prefer to experimentally book and prove. Yet, I have done it in past and if gain a chance, will give you a PNR in future also.
It is on the same lines of general quota reservations where it is 90 days in advance but can be booked from intermediate (where from the train does not depart on the day of originating) stations more than 90 days (91, 92 or so) in advance.