Batboard

Can anyone give me the part numbers required to interface a the HMN4044E W3 head to a XLT5000 (M20URS9PW1AN)?

Best guess based on searching is:
TIB: HLN6885B
Flex: 3085019F01

Those look correct as far as I can tell from the service manuals. This obviously (based on your model #) would be for a low/mid power drawer. If you don't already have it, you'll also need the W series headbridge (1585245E01 is what I show for it).