You are absolutely right in your assumptions and expectations. It is highly unlikely that you will ever see a bloom on Variegata in zone 5/6 without elaborate winter protection measures. Even further south, getting these to bloom well can be a bit iffy. Luckily, this plant is more about the foliage anyway. They make a nice contrast plant in the shade. Sounds like either spot would be fine, so put it where it suits you best. Sorry you had to find out the hard way....yg

Yellow girl is quite right. I would add that I brought my Mariesii with me from New Orleans to east Central MS and have found it to be extremely sun tolerant in both places. (Could be that it was just adapted to New Orleans, but maybe not.) So...I would try that southern exposure on the assumption that the south facing wall might give it an extra measure of protection in the winter. I love it so much I have created an entire white border around it, and it's my favorite garden. Mine will bloom, but I prune it to keep it at a smaller size. (The blooms are lace caps.)