I attend the 3rd one on the list. The rest are miles away ( One is 2 hours drive away and one about 4 hours drive; the latter among them is actually in next city. We have too many cars and too little road space so driving takes time ).
I am trying my level best to attend a 10 day retreat this December with S N Goenka's organization. However it is in actuality, not 10 day but 12 day, as those who have completed 10 days there have told me it is best to take day -1 and +1 off from work also for best effect. That is 12 days off from work. Trying to make it happen; let me see what transpires. Summer is best time to take such a break for me. But they do not allow ceiling fans and at 104 F heat and 90 % humidity ( actual heat humidity feeling of 160 F ) it is bit hard to meditate ( though I am sure monks in Thai forests do meditate under such conditions ).
Oddly enough it is actually easier for an American to learn Theravadan Buddhism than me, a guy who lives 400 kms from where Buddha was born and preached !! So frustrating that Hinduism consumes all in it's path.
There is an organisation called Mahabodhi Society of India dedicated to Buddhist studies. A man who publishes Buddhist books and is an eminent member of the place said to me that there is no way one can find a teacher in Calcutta or rest of India. There are only 2 - 3 and they mostly travel between India and Thailand. In fact he also prevented me from taking formal Pancca Sila vows in Calcutta - saying it is better to visit Bodh Gaya and request a visiting Thai or Sri Lankan Bhikkhu to perform it. He has a dim view of Theravadan Bhikkhus in Calcutta.