If you are interested in doing hunts on S and A rank marks, your best bet is to join American Steaktheory. They have a rotating linkshell (you ask to join when you start a hunt session, and you leave when you are done for the day). To get an invite, send a /tell to one of the LS leaders on the list below. You can use the player finder option in game. I just start at the top and send a tell to each person on the list until I get a response.

http://na.finalfantasyxiv.com/lodestone/linkshell/17732923532804834/

Once you are in the LS, here is the spreadsheet that they use to track the hunts. If you have questions about he spreadsheet, you can ask me in game, or someone from the LS should be able to help.

https://docs.google.com/spreadsheets/d/1_DW9U1N8WaJDF_p1utdY6rbecKioJ5jFFZohXwnKc3o/edit#gid=2138641286