Beginner wanting to buy the first sub and daytona

[Yamazaki]

I am entertaining the idea of adding the first ever sub and first ever daytona to my collection.

I know nothing about vintage watches and do not own any so please be easy on me.

Where is a good place to hunt for vintage? Chrono24?

After some research I found that reference 6204/6205 is the first sub to be produced.

What do you think about this listing? Is it a good buy?

http://www.chrono24.com/en/rolex/sub...-id5029583.htm

After some research I also found that the reference 6239/6240 is the first rolex chronograph that had daytona on the dial. So this is the reference I want to buy. What do you think about this listing?

http://www.chrono24.co.uk/rolex/dayt...-id5112392.htm


Thanks