Minimum Time for I140 approval

Hello,

My 6year period on H1B visa ends on 12/13/2020 and currently my GC process hasn’t been initiated. If I/employer start the GC process in Oct 2019, do I have enough time to get I140 and initiate the visa extension process prior to Dec 2020.
Also if I do not get my I-140 till then, then can I extend my H1B for another 180 days.

Thanks
Kiran

You can get better idea by looking at the current processing times online.

you can request any term extension only when you are eligible for such extension.

To initiate the GC process, how many minimum paystubs are required? I am considering 15-18 months of time for getting I-140 approval after initiating the GC process.

you dont need any pay stubs to initiate any GC process