Sorry for the bump.
Just an update for anyone who cares.
I went home, checked the supports from the night before. All was secure, but it seemed just a little less rigid than I would have liked. I took my old rack, tore it apart and used a seat-post clamp to add two more supports at the front. After I got done, I headed to the store and got some milk, soda, sugar and some other items. I loaded them into the baskets and road around the neighborhood for a while before heading home. All was steady and I'm back to commuting again!

Here are some shots of the new supports and mounting system:
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Thanks again everyone. Have fun and ride safe!