Best Practice for monitoring LACP interface

I've got an LACP connection from my HA pair of FortiGate 600f's to the rest of the environment.  There are 2 physical ports that are under the "LACP_Trunk" 802.3ad aggregate interface.  What's the best way to monitor these interfaces for HA failover?  Is it best to monitor Port1 and Port2 (which is the indication that I got from an article about Multicast https://community.fortinet.com/t5/FortiGate/Technical-Tip-Best-practice-HA-monitored-interface-configuration/ta-p/214928 ) or is it better to monitor the "LACP_Trunk" 802.3ad aggregate interface directly?
TIA!