Hi Gusso, I used a few strains from this guy and I know another ebay seller personally (yeasterbunny) and also used his products.
I suggest you to take the half of the package and make a starter (my preferance is 700 ml with 1.060 SG) out of it, then cold crash, and dry the slurry in a parchment paper in room temp or in your oven with only the lights on. You will get 7-11 g of dry yeast depending the strain and using 2 g in a 5 gal batch will be more than enough. With this method I never had a spoiled beer and I can say I tried at least 8 strains by far (and having 10 others waiting for me haha).
Let me know if you have any questions!
Still in garage fridge with tap but better lighting on this one. Such a smooth mouthfeel. Head would be nicer in one of my kegerators, though...I didn't have room in my kegerators so I just put a faucet on the keg to try this out. Pretty damn good and complex. Very different than any Kveik I've used before. I get fig, honey, and slight farmhouse flavors. Very interesting yeast. Kind of a mild Belgian profile.