1.Actually try to understand the system. Our batch was named as SDPA78G1. It means South Delhi Centre,PassOut batch,17-18 season and G1 class. Now you can easily guess that the first batch that starts from April will be named as SDPA78A1,then A2 till A5. Then B lot starts after 1-2 week after A lot.
Similarly,at the starting of July, generally SDPA78F1 will be made,since this is the time most of the students who already have cleared JEE Advanced comes to join the institute,that's why these batches are considered good. There's nothing special in the name.I hope you understood the system. Likewise,there's a similar system for 2 year and 4 years students. About number of batches, we had A1-A5, B1-B5.......till H1-H3 so in total 38 batches of about 40 students each.
Whichever lot you get A/B/C..... Always try to get the first batch I.eA1/B1/C1/....H1. This is purely based on your performance in XRET and JEE Mains and Advanced.
2.See it's almost impossible to get the best teachers of all the three subjects. You would probably get 2 very good teachers and 1 normal teacher in all batches. In lower batches, teacher tend to work much harder on each student.As far as Sankalp batches are concerned,they have the best teachers. But ,if you go by my experience,if you make a good relationship with your teacher in first two months,you would hardly want to go to Sankalp batches. I have seen live examples of these. Remember,even if you can connect with an average teacher,you would love to study. He knows everything that's atleast required for JEE. You aren't going there to prepare for Olympiads,right. Just have faith in yourself and your teacher.
3.You can refer to above point.
4.Haa, droppers ka ek Sankalp batch hota hai. Last year about 15 students the. Agar acha perform Kiya to SuperSankalp me promote ho jaoge. Don't think so much,just focus on studies. Everything else will take its shape.
5.As far as I remember,my batch had 35 students and if I m not wrong 23 of us scored 200+ in Mains,that's a significant figure. I have no clue about Advanced about entire batch but many of my friends have scored in the range 180-140 including me.
At last, never doubt once you take a decision. Just give your best everyday. You will see the results later on.