You are a kind and patient person, lisa. Thank you so much for your help.
In the end, it seems that I needed to not only make sure the top and bottom hole were preserved from the cylindrical template, but also I wasn't able to use the Bevel and Indent tools at all ... that's what was causing the radiant lines from the bottom left corner of the UV map, and the holes in the map too I suspect. I reconstructed my shape from scratch being careful of these two things, using Spike (+ & - values) instead, and it imported into SL fine. Yay!