Personally, I would opt for the full sun with less wind site. Why.... The newly containerized plant will be growing a root system in both locations, but the drying winds can overstress the still, rudimentary root system, and then you tree will be stressed. So, I would chose the more sheltered of the two locations.

Sinking the container into the surrounding soil will help keep the root-zone cooler, especially, if you pile mulch up the sides, which will shade the container. Cool feet...and a hot head. Try to keep the medium damp.

In Zone 5b, you will no doubt, lift the container for winter storage. If you must, spade sever the roots that have grown outside the container and into the surrounding soil. The lift out the bucket. As your tree grows larger, you will need to move it into a larger capacity container. My trees are in 18 gallon storage tubs that are sold by Home Depot. I drill holes into the bottom sides, fill them with a quick draining mix, and plug in a tree. Done.

Good luck.

Frank