Don't use IGBT.
Don't use IGBTs. At 1.2v ON you will have to dissipate 350 watts at 100% on.
At this voltage you need to use MOSFETs with a low RDSON if you wish to have not much heatsink.
Use one of the IR driver chips that can detect that the MOSFET is saturated,
and just feed the output of the IR device to the gates through individual gate resistors. 220 ohms is a good starting point.
Actually you don't want to switch them on too fast, as their maybe current flowing through a flywheel diode (if you use one and probably will) during the off time. You must make the turn on time is longer than the reverse recovery time of the flywheel diode, else the MOSFET will see a short circuit to supply for the r-r time, and make lots of extra heat.
Use multiple supply capacitors in parallel for low ESR, but because of inductive load, peak currents may be lower than you think. 3 x 2000uF in parallel probably more than sufficient. If they get hot, add more.
Wire all the drains individually to a common point.
Wire all the sources individually to a common point. (negative of supply)
Use individual gate resistors. Important.
Wire common of driver to the common source point with a separate wire.
Do not daisy chain any of the power wiring. You might end up making a big radio transmitter if you do.
If you use 6 SUP75N06-08 Siliconix MOSFETs in parallel they will need 30w heatsink for each one.
The 75 is 75A, N is N-channel, 06 is 60v and -08 is 8 milli-ohms.
Make sure you select a device with very low RDSON otherwise you will need a lot of heatsink.
That is based on 50 amps per device, with an RDSON of 0.008 ohms
3 3"x3" finned heatsinks will be about right. 2 devices per heatsink.
Super X3. 3600rpm. Sheridan 6"x24" Lathe + more. Three ways to fix things: The right way, the other way, and maybe your way, which is possibly a faster wrong way.