The auction I found was for multiple bags of 16 packs. You get free shipping if you spend $160, which equals the album and 14 of the 16-pack bags. Will that affect my odds worse than buying boxes? I had no idea that odds would be better in 100 pack boxes.
Yep, the more you buy from different sources (and this usually means different articles), the more doubles you're prone to get... Unless you have an amazing luck to get opposite contents.
I don't know how Calciatori is, but I'll give the WC 2010 World Cup boxes example: if you buy a 100-packets box, you'll probably get all 500 stickers different... Now, you don't need to be a genius to understand that this is manipulated by Panini, but in a good way (the bad way is when a collection has rare stickers and you notice how they only put half of what they should put)... Now, if you 10 packets x 10 times, how many doubles you think you'll get? For sure, zero is not an option, not even 50.
And this can be worse if the collection has rare or very easy stickers... So in the end, for your case, it's better to buy 100-packets boxes, unless Calciatori boxes also have a lot of doubles... Maybe watching unboxing videos or asking someone else.