We dropped my engine and dove into investigating my 3rd gear grind. When we opened the drain plug to empty $70 of Swepco into a catch basin a gear tooth clattered across the garage floor. It didn't get better from there. Turns out the 3rd gear dog teeth are almost completely rounded off and the nearly new syncro ring is worn smooth. It must be substandard parts because my coach at VIR said I was a very good shifter :)
Screw it, I'll just buy a GT3 Cup for next season.
On another note, I've seen the secret weapon. I cannot say where but I can say it is close, very close . . .