DIY申請eb1a 和niw一問

準備自己申請eb1a 和niw. 請教過來人：
我是應該同時準備好兩個package還是一個一個的申請比較好？有什麽需要考慮的麽？

should I submit them at the same time? when filling both forms, saying that
I haven\'t send any applications before?

or should I submit one by one? for example, submit niw first, after getting
the Receipt number then submit eb1a. When submitting eb1a, refer to the
first receipt number for NIW?

or it doesn\'t matter at all?

thanks very much for your advices!