So, after reading these various suggestions, I looked in my styrene stash. I only had .030" rod, which was too small. So I took a piece of .040" square stock, twirled it in some sand paper (with my fingers) to round and taper it, put it in the hole with some liquid styrene cement, and trimmed it off. After drying, I drilled and tapped this morning - success!
Thanks all!
