DIY申请eb1a 和niw一问

准备自己申请eb1a 和niw. 请教过来人：
我是应该同时准备好两个package还是一个一个的申请比较好？有什么需要考虑的么？

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!