Fighting one or two giants are easy, but fighting a group? that's one thing to consider.
You can't become a "Giant slayer" just because you killed one, you have to have killed a plenty.
That being said, I do think giant killer is a wrong title as your giants are WAAAAAY to strong and WAAAAY to tall for someone to kill with a blade, even with poison. At that height, the most weakest point of the giant is the feet. big, range weapons will penetrate those but they are a burden to carry by one man.
A more plausible approach might be, The Giant killing army.
Your army can, scatter long, steal spike, drench them with poison, then cover them with forestry.
Your main weapon for killing them will be ballistas... Lots of them, as they are the weapon with the highest percentage of killing a giant without any casualties.
There should be one improvement however, you ballista must have a reloading mechanism similar to a Van Helsing's repeater crossbow because you need to reload as quickly as possible, but pack a punch too.
one of your problems however, is that you got 100 persons, give or take that some of them are women, or grandparents and kids, your army lacks manpower, 50 might hold for some time.
I also suggest to be on the defensive rather than taking the fight too them, setting up traps is the best way to kill the giants, you need all the manpower to protect your people and ensure continuity of the human race.
another problem is giant carcass, yeah you killed them, but if they die close to your encampment then then stench will kill you as well, so you better plan your traps, how you set your encampment, and how you can engage the giants with your ballistas on the encampment, and during the move.
you will have a pretty busy life if you ask me...