The SCIII is slower. SCIII (slowest), Sage SLT (middle) TFO Pro (fastest). There is probably a 10% spread from the SC to the TFO.

There is one other thing you can do (although NOT on the list of any purists) - overlining. It is a wonderful way to slow down the action a bit and the rod will load faster making the overall effort easier for most casters. So ... buy a 4wt blank and use a 5wt line, if needed.