So with 470v the no load speed is 9635 and at 410 (nominal voltage) the no load speed is 8405 which one do I use nominal or full voltage?
I think it's most realistic to use nominal voltage.
No idea how you come to that 4000A figure. the spreadsheet tells me it should be around 9000A at Pout= ~2.7MW. Still no realistic, as battery resistance was not taken into account. if you want a realistic figure, you have to add it to Rm in the spreadsheet. Guess it will be around the same as Rm, yso max Pout maybe roughly 1.3MW.
Still, these numbers are not realistic. As pointed out in PM, you will run into serious heat problems above 2000A.
I don't know if the voltage will be able to push 4000 amps...
what do you mean with this? The voltage is enough to push 9000A if your battery had no Ri