H1 cap exempt

I am from India. My employer is filing H1B under cap exempt category in 10 days time. I do have visitor visa B1/B2 visa of US. Can I enter US on B1/B2 and start working when my petition is approved or it is mandatory for me to get H1B visa stamping from US consulate, New Delhi before entering US?

Or, I can enter US , start working and later get the visa stamping from outside US?

If you enter US on a B1/B2, then a change of status application will be required for your H1B to be activated. Travel outside the US is not needed but staus change request must be filed. Also, your stay in the US might get randomly restricted to 30-90 days because you are a tourist. I suggest waiting and getting your H1B stamp done in Delhi