Going by the example you specifically mentioned:
It's my understanding that the club you pick for an 'intake feeder', a club which gives you the chance to recruit foreign youngsters, is largely aesthetic and nothing more. The one definitive feature it means is that if you pick a German feeder for that purpose, such as Braunschweig, you WILL begin to see the odd German player in your youth intake. The same applies for a Brazilian, Argentinan or East Timorese club, whatever the option. However, whether that club is Sao Paulo, River, Fima Sporting or some random 3rd division side, is irrelevant as far as I'm aware.
As a result, I will almost always favour 'better' nations - Germany, Brazil, Spain over more obscure nations. If I'm given 3 or 4 poorer options, then I'll go for the team with the best facilities, just in case.