I studied from Hyderabad and I can assure for one thing that batches for dropper will be of small strength and will have more attention to student by faculty. So wherever you apply ensure these things first.
Amongst the Chaithanyas and Narayanas the problem is that some of their branches take loads of students just for business sake and and not all their batches receive same quality of attention. If you consider Narayana the hostler options would be better and chackout how many batches for droppers that particular branch runs. Also their more priced courses would be better and somewhat risk free.
Other good options are FIITJEE, Mega as far as it goes. FIITJEE has many branches so you have options.
One year of regular, dedicated JEE preparation will be helpful to crack the exams. Intact around half the population of IITians are droppers. All the best for your preparations.
Among the ones you mentioned FIITJEE, Mega, Ramiah are the best in those, but for Ramiah there's an entrance test with very limited seats.