Same Client different employer -- First time H1 stamping

I am MS student on H1 after completing OPT-extn now planning for H1 stamping.

My Senario. I have a H1 transfer on the same project.

Client A -- Prime Vendor B -- Emp C -- First H1 with Emp C
Client A -- Prime Vendor B -- Emp D -- H1 transfer to Emp D

Please suggest or answer based on your experience:

1) Is it advisable to go to Canada for this scenario...?

2) Chances of 221g

3) what is possible answer if VO asks: how come you are working for a longer duration with your client ..?
  1. As you have done Masters in US, you can go to CA.

  2. There is always chance of 221g getting issued, especially as your case is EVC model. Have contingency plans

  3. What do you mean longer duration? You are working legally for the client through the employer holding your 797

Thank you very much Saurabh for responding…!

I have been working legally with the same client but I have changed my employers.

I wanted to know since I have longer duration with client and vendor (>1yr)
and shorter duration with current h1 employer (<6months) will it create any problems …?

I don’t think it will be an issue.

Thanks Saurabh for responding so quickly.

my situation.
same client and vendor - 1yr
opt emp A - 8months; H1 emp B - 2months; H1 emp C - 4months

I am bit concerned about stamping and 221g. I am not sure what should be the necessary documentation to support stamping for my case …?
Will the client and vendor letter be enough apart from the standard documents from employer…?

You will need contract letters b/w client and vendor, and vendor and employer. In addition, you will also need information on how your employment satisfies employer-employee relationship requirements. Other than that, one needs the usual documents from the employer.

Thanks Saurabh. Greatly appreciate your help…!