Charles,
Congrats on the win and getting the RPM's down at the finish. Since your season is almost over, I would probably just look at repairing your converter. So, I would contact Trans Specialties first and see what they will charge and what they think about the slippage.
I think that the spragless converters usually have a little more stall than sprag converters, but I don't think that the spragless is supposed to slip more on top end. The slippage on the top end is the efficiency of the fluid transfer. The size of the converter shell, distance between the fins of the drive and the fins on the pump cover, the torrington roller bearing running clearance, and how much the fins flex all have a part in the overall efficiency of the converter.
JMO
Bill