Got Fortune top 10 offer, how to extend H1B?

Got an offer from a top 10 fortune company. Company will sponsor GC. I have used up 3.5 H1B in univeristy only 2.5 years H1B left. Questions

(1) In big company, how soon can they start GC petition? after 2 years?

(2) I have to submit 140 petition one year before H1B ends in order to extend H1B?

(3) If I go to EB3, how long will it take from PERM to 140 submission?


Thanks for your help.