Intel SSD DC P3608 4Tb max payload size

Dear Intel Community,

I have a question regarding Intel SSD DC P3608 4Tb max payload size.
I'm going to use it in the system with Xeon E5-2699 v4 and custom FPGA board. As far as I understand, Xeon E5-2699 v4 is able to provide 256 byte max payload size for the PCIe IIO in my case (according to the p. 6.13.3.19 in the "Intel Xeon Processor E5 v4 Product Family Datasheet Volume 2"). Also, according to the infromation I found, BIOS will set max payload size in the system based on the minimum supported value for the devices in the PCIe tree.

I'd like to determine which payload size I will have for that particular PCIe tree, so I can build a firmware for the FPGA according on the actual payload size value.

Best regards,

Igor.