I would check with your vet. It's good that you have done your reasearch on this and it's even better that you will be having him neutered. I don't have any experience with giant breeds so I don't know what the best thing to do is. I would try to get 3 different opinions: from a few different vets, a few different (responsible breeders), and a few different giant breed rescue groups. These 3 sources will most likely have the experience with this situation. You don't want to jeopardize his health if neutering him before 2 will cause problems.

Can he be boarded at your vet?