LTC3350 MOSFET selection for a given application

Dear Analog team,

I am designing a power backup solution with LTC3350 with the following characteristics : Input = 24VDC - Output in backup Mode = 6V/5,6A. None of the MOSFETs shown in the different applications seem to meet my requirements (either because VDSS is too low, or Rdson too high, or just because of availability ...).

I have identifed a MOSFET from Infineon which seems to be every "adequate" for my application (both at input and output sides) : IAUA250N04S6N008 - VDS=40V - forward current : 340A – Rds on = 800µOhms  - Vgs=-20V/20V – Vgs threshold=3V – Power dissipation = 172W

I have also identified Vishay SIR680LDP-T1-RE3 which is less expensive and might be a better choice ... :  VDS=80V - forward current : 130A – Rds on = 2.8mOhms  - Vgs=-20V/20V – Vgs threshold=2.5V – Power dissipation = 104W

Before moving forward, I would be grafeful if you could tell me if you think that these MOSFETs would  be ok or if you see some items that I should take care about before going forward (note that I am now using LTSPice for simulating my system, which is very helpful ...)

Best Regards

Thierry