For anyone who might be interested, I wrote a script to test the limit on DHCP server leased addresses for the switch. The limit is 512 addresses for the entire DHCP server (that includes all pools).
I can't find anywhere in the documentation the maximum number of addresses that the built-in DHCP server can lease. I know on some Dell switches it's very small (like only 256 address on the N-series). I am able to create a pool with over 8000+ address, but I don't want to start using it and then find out later that I can't actually use that many addresses.
X-Series DHCP Server lease limits