Without knowing your electrical load, there's not a recommendation I could safely make. Most likely, you could use a pair of the 1100W PSUs and get along just fine. However, I would log into the iDRAC and you should be able to check your power balance at the System > Overview screen, if you scroll down a bit. For example, the system I'm looking at is using 313 watts. The Configuration > Power Management will also provide some insight on how your power is set up.   Once you know how much power is being used, you can figure how much additional power will be needed.
How big (W?) should the PSU be in a PowerEdge T640 to run a dual Xeon Silver 4110 setup with 16 discs?
PowerEdge T640 how big PSU for dual Xeon Silver 4110