I'm also a newcomer but I think you should zoom out a little more to see the history of the trade. From what I understood I think that (going from left to right):
1st drawn base: ok
2nd: it doesn't have a good runner up
3rd: If you have a base right at the bottom of the whole graphic in the last days of August it's ok
4rd: (first one after the runner up) is not a good base, you don't have a strong depression nor a good run up
5th: same as the 4th, a little better because it has a nice drop but not a good runner up
6th: it's a nice base.