F-1 to H1B , which is best process COS or Consular process

[kumarm.sql]

I came to US on valid B1 visa and converted to F1 Student(COS). Now my graduation date is on April 2016 and planning to apply H1b even though I am eligible for OPT.

1. Which is best option for apply H1b through COS or counselor process(CP)?
2. If my H1b approved by COS/CP ? can I still be on Student status and work on OPT(1 yr) + STEM extension (I know STEM ext. approval is in pending decision, but I want to utilize my OPT)
3. If H1b approved by CP , can I eligible to work immediately? Or do I need to go my home country for stamping?
4. If employer agrees is it possible to apply GC , while Ia am on OPT?

Thanks in advance.

[adshah84]

1) My preference is COS

2) If you want to utilize your OPT then CP is the only option

3) If H1b approve by CP then you can not work on H1b until you do stamping

4) No you can not file GC while you are on OPT