Hello there. Well your pretty much right. You have the right to choose from 2 bases. For exsample 1. Dublin 2. Girona.
Now they will to 70% Give the base you want,but remember they can also say no u'll have to go to a totally diffrent base if its your choice or not !
I have been based in CRL and in HHN. Charleroi is the best base out there !
HHN is not bad but there quite a few things what i didnt like.
About madrid and girona. I heard madrid isnt that good as it sounds,and is being said,but girona seems to be pretty nice.
Well if i may say choose either Charleroi or Girona. Forget madrid!
Best of luck !
Best Regards,
Claudinho