@wtdrisco There should be no Problem if the core counts don't match. you just can't place a VM that has 32vCPUs on the 24 core host.
But one thing you should have equal over all hosts is the amount of network interfaces and also have them configured equally (which should be done by XOA/XO form sources). Otherwise a VM might not migrate because a network Interface is missing on the target host.
Also passed through hardware might prevent migrating to another host.
I run a pool with two diffrent hosts, one has 8 Cores and one only 4 cores, also one has 64 GB RAM and the other one has only 32GB and in this limitations I can easily migrate VMs back and forth between hosts.