So running some math on the starters and the boosters and it is definitely something that is mind boggling.
In order to get a full set, we will need to purchase two of each of the starters. This is a combined total of 14 rare cards combined in the 4 starter packs. Now, one of these can be excluded, in case you want to be crazy and run 3 or 4 FO Stormtroopers.
So lets run with some examples of both 6 and 7 rares being used to calculate some numbers for us.
Excluding the officially designated starter pack rarity cards, the set is comprised of the following:
Legendary - 17 cards
Rares - 36 cards
Starter Rares - 7 cards
Uncommon - 42 cards
Common - 58 cards
With the released information we have so far, the average number of Legendary cards in a booster box is supposed to about 6. With that assumption, we will then pull 30 rare cards out of each box. Rare cards for the set total 43, however that is reduced to 36 if we exclude those that make it in the starters.
This translates in to 16%(14% excluding FO Stormtrooper) of the rares that we blindly pull out of boosters will be those we don't need. In terms of actual pulls per box, this translates to 4.8 rares per box(4.2 excluding FO Stormtrooper) in to worthless cards.