It is no difference to the manual assignment previously. Most managers used to assign heavily on Attacking & Physical attributes of Strikers and spread it out for midfielders normally attacking, defending & physical in that order. well, you get the idea.

If you play on the web and manually assign, well, the rule of thumb for most managers is X, X-5, X-10 or X-3, X-10 (ball park estimation), X being the main attribute.

If you play on mobile, I guess jst selecting the two main attributes shd suffice.

I don't think there is any difference in terms of progress jst that one is manual and one is auto assignment.