Question about selling Rolex datejust! Help !

[kit22]

Hey everyone I am new to this forum and have a question for you guys since everyone here seems to be very serious. I have found a local jeweler in my area that offers what I think is some good deals on Rolex's. I am very into online selling and am wanting to purchase some watches in order to sell online. Now I have two questions.. The first one is: What model rolex is more desired/ valueable would it be the Rolex Date or Rolex Datejust?? My second question is: What years of These two Rolex models are most valueable? Would you reccommend to buy a early 1990's model Rolex or would I be better off buying a 1970's model? Since its 1970's model would this make it a vintage watch making it more valuable?? I really need help you guys thanks for looking!!