Mark VIII (P# RF123) fans do not have the same motor as the Taurus 3.8 fans, and they have 18" blades compared to 17". Output is said to be 3000+ CFM on low and up to 4900 on high
Similar RF125 fans use a Lincoln motor on a taurus 17" fan, which still gives good CFM, but not RF123 output. RF24 and taurus fan’s are the ford motor on the 17" blades which put out something like you said 2500 low and 3900 high.
Maximum draw on startup for either is still under 45 amps I believe, with average high draw of 30-35 for the bigger RF125 motor, 25-30 for the RF123.
Sounds like you have a solid setup though, I’m overbuilding the hell out of mine, but yours is more than enough - is the Z31 switch ballin’ or why did you choose it?