I’m planning to file an NIW I-140 in March 2026 and need advice on Premium Processing given my H-1B timeline:

1. H-1B valid until Nov 2027
2. Regular NIW takes - 22 months; PP takes 15–45 days ($3,300)

Employer can sponsor PP only in Nov 2026

Options:
1. File with PP myself → approval - Apr 2026, 19-month margin
2. File now, wait for employer PP → approval Dec 2026/Jan 2027, 10-month margin
3. No PP → approval Jan 2028, would miss H-1B deadline

Questions: Is PP timeline realistic for NIW? Is 10 months enough? Can H-1B be extended with a pending I-140? How important is an advisory letter from a previous manager?

Any advice or experiences would be appreciated.