Oh man! you have no idea how awesome it is to see people trying to find strategies to beat/speedrun your game! you guys made my day!
Just a tip: we figured out a few comments back that if you get SUPER LUCKY you could hire 2 extra workers in the first day and start day 2 with 3 workers.
I don't know if that would help getting to day 7, but I leave that to you ;-)
Thanks for playing!