Getting H1B filed for one company and STEM extension from another company


I got an offer from a company which is willing to do my H1B visa but it is NOT e-verified so it cannot give my STEM extn.

My options are:

  1. Get this company file my H1B through premium processing and hope that if everything goes well, I get my visa approved by May first week. If it doesn’t I still have time to file STEM extn through a consultancy.

  2. Get this company to a corp-to-corp through a e-verified consultancy and still ask this company to file my H1. In this case consultancy will take care of my STEM extn and the company will take care of H1B filing.

My question:

A) Which option is more safe and feasible?

B) How soon the result come through premium processing? I think I should have enough time to file for my STEM extn.