if i had that type of empty space i would actually try growing in big containers since
then you can control the size and the food the plant gets. whereas you'd probably end up
with humongous trees in the end. god only knows how far those roots can reach into the
ground if you give them a chance.
and for your seeds i've bought cheap kulu seed bank seeds and all of them germed no problem and they seem to be strong.
since it'll be your first grow i would suggest that.
if you do decide to plant in the ground though, like what farmers do, prepare the soil so it's aerated and that it's got good nutrition for the plant.
here's a list of different reviews for the major seedbanks on the internet. this page explains
which ones to go with and which ones to avoid:
http://www.seedbankupdate.com/su.html

good luck