Under promise and over deliver is still king.
“I cannot guarantee something won’t go sideways. I need at least 3 weekends of overtime available to be certain before it’s released.”
Deliver it 10 days later. Or 12, after relaxing for a day or two.
Your timeframe stands. New project? Do it again. Give yourself ~100-150% extra room.








Nobody asked you to not summarize, but here you are.