I don't know the polymerized Tung oil but everyone here say to go for the Tru oil, I will use it for my neck.
I seen 2 coats of Tru oil and then a wood wax should be fine, but I think that to check instructions isn't a bad idea.
I know that Tung oil is a pure oil without any addition. Usually danish oil (used to finish necks) was a mix of tung oil and polyurethane lacquer... something so.
But now a lot of people are using Tru oil instead Danish oil to finish necks and bodies too.
Start with 500ml. I believe you should be able to finish your body and neck.
And if you perform a search, there are a lot of posts about oil finish.
Hopeing that can help you.
Gian