H4 visa application during primary applicant H1 transfer

Earlier this year, my husband and I got married. I am currently in india and he is in US on a H1B with employer A and is possibly looking at transferring his H1B to employer B. I have a Visa slot available this weekend Sep 6th. So my questions are:

  1. If I get an H4 based on employer A details and travel to US 2 months down the line my husband’s H1B will be tied to employer B. What documents will I need to bring to support my immigration?
  2. To avoid the above scenario is it recommended to process my H4 once my husband’s H1B transfer is complete?
  1. Nothing specific. You need to carry your spouse’s H1B that is currently used which is from B, employment letter, etc.
  2. It is ideal, if you can postpone…but should not really matter. Alternatively, you could go to US and then he transfers.