Visa stamping when H1 has dropbox and H4 needs interview

[Ajay71]

I am on H1B and got my extension approved in 2018. My wife did a H1 to H4 COS (change of status) and got her H4 approved at same time. We will be travelling to India and doing visa stamping.

I am eligible for dropbox .My wife is not eligible for dropbox due to COS and has to appear for interview.

I see 2 possible ways to co-ordinate both dates(drop box and interview).

1. Can she give the interview the same day I submit documents to dropbox?At this point my H1 will not be stamped yet so is she eligible to get H4 stamp?

2.We have to wait till my H1 is stamped and receive passport back and then only she goes for interview. In this case, how many days apart should our dropbox drop date and interview appointment date be?

Any other suggestions are welcome.

Thanks