Transferring to H-4 at this point is not a good idea. I believe even for NSC
, it's more likely you will get card than RFE. A food for thought, if you
are current in September, how about you send H-4 transfer request only when
you see online update that shows there is a RFE coming? If in unfortunate
event when your case is refused, you should still be able to stay here
legally with a pending H-4 case. Remember, if you were single, you would
have no choice but wait for card or RFE, in any way, it's perfect legal to
stay in AOS till decision is made. Your spouse's H-1B is more like a
valuable back-up, not a liable burden.
Only my own humble opinion, you should definitely consult a lawyer on this.