Ca Final best costing faculty old course

Hi,
with regard to subject, I have written my may 19 attempt n score 51 in costing as I have done self study and studied only from PM. I couldnt clear as I lost in aggregate. I prepared for Nov 19 attempt with same PM pattern + past question paper and RTP. this time costing paper was very tricky and I didn't write it well.
I felt might be I'm conceptually not clear with topic due to which my mind could adopt with changed question pattern. hence want to prepare for May 20 attempt by taking pendrive class. I don't know which faculty is best for conceptual clarity. few faculty like sanjaya agrawal, purushottam agrawal, parag Gupta, sankalp kanstadia are available but I'm confuse which faculty is best among them. plz give me true opinion as its gonna be my third attempt for second group